LIBRARY 

OF    THE 

UNIVERSITY  OF  CALIFORNIA. 
Clots 


MODERN 

ELECTROLYTIC     COPPER 
REFINING. 


BY 


TITUS  ULKE,  E.M., 
Consulting  Eledro-Cbemist,  *  Member  A  E-C.S.  and  A.IM.E. 


FIRST    EDTTION. 
FIRST    THOUSAND. 


UN!/,. ,:  3  IT  Y 

OF 


NEW  YORK : 

JOHN    WILEY  &    SONS. 

LONDON:   CHAPMAN   &    HALL,  LIMITED. 

1903. 


GENERM 


1903, 

BY 

TITUS  ULKE. 
(Entered  at  Stationers^  Halt) 


ROBERT  DRUMMOND,   PRINTER,   NEW  YORK, 


INTRODUCTION  AND  ACKNOWLEDGMENT. 


THE  great  difficulties  encountered  in  preparing  the 
following  monograph  can  be  fully  appreciated  only  by 
those  who  have  undertaken  a  similar  publication,  and 
might  have  prevented  the  consummation  of  this  work, 
undertaken  at  the  request  of  several  distinguished  foreign 
engineers,  had  I  not  been  assured  of  the  cooperation  of 
these  gentlemen  and  of  some  of  the  leading  electro- 
chemists  and  refiners  in  the  United  States. 

It  is  a  well-known  fact  that  the  managers  of  but  few 
electrolytic  plants  grant  technical  visitors,  and  especially 
writers,  access  to  their  works,  and  that  it  has  hitherto  been 
extremely  difficult  or  impossible,  therefore,  to  secure  accu- 
rate descriptions  of  certain  American  and  European  refin- 
ing appliances,  methods,  and  works.  Fortunately,  I  have 
had  the  opportunity  of  personally  inspecting  many  of  the 
most  important  electrolytic  refineries  in  the  world,  in 
several  of  which  I  have  worked,  and  am  therefore  enabled 
to  present  certain  desirable  information  accurately  for  the 
first  time  in  print,  and  to  supply  close  estimates  of  other 
much-sought-for  data. 

Requests  for  information  were  addressed  directly  or  in- 
directly to  practically  every  electrorefiner  here  and  abroad, 
with  the  object  of  making  the  following  monograph  as  far 
as  possible  an  authoritative  accurate,  comprehensive  and 

iii 


1 17590 


iv  INTRODUCTION  AND  ACKNOWLEDGMENT. 

thoroughly  up-to-date  handbook.  Its  scope  is  indicated  by 
the  numerous  items  of  the  table  of  contents. 

Every  electrolytic  copper-refining  plant  in  the  world 
that  is  now  in  commercial  operation,  I  believe,  is  herein 
tabulated  with  its  actual  or  estimated  output,  arrangement 
•of  electrodes,  location,  etc.,  and  is  described  as  fully  as  a 
personal  inspection  and  inquiry,  examinations  of  American, 
British,  German  and  French  patents  and  literature,  or 
special  means  of  securing  information  at  my  command, 
permitted.  The  data  thus  gathered  at  the  expense  of  con- 
siderable work  will,  I  trust,  be  appreciated  by  copper  re- 
finers especially,  and  aid  in  stimulating  progress  not  only 
in  their  rapidly  extending  art,  but  in  electrometallurgy  gen- 
erally. 

I  take  pleasure  in  acknowledging  my  indebtedness  to 
Mr.  Lawrence  Addicks,  Raritan  Copper  Works,  Perth 
Amboy,  N.  J. ;  Mr.  Ottokar  Hofmann,  Director  of  the  South- 
west Chemical  Co.,  Argentine,  Kan.;  and  Mr.  R.  L.  White- 
head,  Manager  of  the  Seattle  Smelting  and  Refining  Co., 
Seattle,  Washington,  for  permitting  my  use  of  their  ex- 
cellent articles  in  The  Mineral  Industry,  vols.  ix  and  x; 
and  to  Dr.  Jos.  Struthers  and  the  other  editors  and  pub- 
lishers of  the  Engineering  and  Mining  Journal  and  Min- 
eral Industry  for  a  similar  kindness  extended  by  them ;  Mr. 
Wm.  Thum,  Ass't  Sup't  of  the  Balbach  Electrolytic  Copper 
Works,  Newark,  N.  J. ;  and  Mr.  J.  B.  C.  Kershaw,  Electro- 
chemist,  London,  for  their  valued  cooperation;  Prof.  W. 
Borchers,  Aachen,  Germany,  for  placing  technical  data 
in  his  "  Elektro-Metallurgie "  at  my  disposal;  Mr.  Victor 
Engelhardt,  Chief  Engineer,  Siemens  and  Halske  Co., 
Vienna,  who  assisted  in  obtaining  information  regarding 
European  plants  and  furnished  descriptions  of  the  Austro- 
Hungarian  refineries;  Dr.  Gustav  Koelle,  Director  of  the 
Von  Siemens  Copper  Works,  Kedabeg,  Russia,  whose  in- 
teresting description  of  the  Kalakent  Works  is  given  in 


INTRODUCTION  AND  ACKNOWLEDGMENT.  V 

Chapter  II,  and  to  the  following  electrochemists,  metal- 
lurgists or  engineers  for  rendering  valuable  assistance,  or 
managers  of  refineries  for  allowing  me  access  to  their 
plants : 

Mr.  A.  L.  Walker,  Manager,  Perth  Amboy  plant  of  the 
American  Smelting  and  Refining  Co.;  Mr.  Ed.  Balbach, 
Jr.,  President,  Balbach  Smelting  and  Refining  Co.;  Mr. 
M.  B.  Patch,  Superintendent,  Buffalo  Copper  Works; 
Mr.  J.  C.  McCoy,  Manager,  Raritan  Copper  Works;  Mr.  W. 
A.  McCoy,  Superintendent,  Raritan  Electrolytic  Works; 
Dr.  James  Douglas,  President,  Copper  Queen  Cons.  Mining 
Co. ;  Dr.  Edward  Keller,  Anaconda  Mining  Co. ;  Mr.  J. 
T.  Morrow,  Superintendent,  Boston  and  Montana  Cons. 
Copper  and  Silver  Mining  Co.;  and  the  superintendents 
of  the  Anaconda,  Baltimore,  Blue  Island,  and  Nichols 
refineries  in  this  country,  and  of  the  Mansfeld,  Oker, 
and  Altenau  refineries  abroad,  as  well  as  the  following 
engineers:  Mr.  J.  R.  Watson,  Lake  Superior  Power  Co.; 
Mr.  J.  H.  Hoff,  American  Bridge  Co.;  Mr.  Willard  Pope, 
Canadian  Bridge  Co. ;  Mr.  A.  L.  Roby,  Wellman-Seaver 
Engineering  Co.,  and  Mr.  G.  J.  Rockwell,  of  the  Allis-Chal- 
mers  Co. 

TITUS  ULKE. 

NEW  YORK,  March,  1903. 


CONTENTS. 


CHAPTER  I. 

PAGF 

DEVELOPMENT,    METHODS,    AND    APPARATUS    OF    ELECTROLYTIC 

COPPER  REFINING 1-55 

Historical  Data,  i .  Cost  of  Producing  Electrolytic  Copper, 
3.  Definitions  and  General  Principles,  3.  Comparison  of 
Methods,  7.  Efficiency  of  Plants,  14.  Stock  of  Metal  in 
Refining,  14.  Sampling  and  Assaying,  16.  Chemistry  and 
Physics  of  Refining,  17.  Treatment  of  Solutions  and  Making 
Bluestone,  27.  Treatment  of  Slimes,  47.  Resume  of  Modern 
Practice,  51.  Tables  giving  Outputs  and  other  Data  of  Elec- 
trolytic Copper  Refineries,  52. 

CHAPTER  II. 

DESCRIPTIONS  AND  VIEWS    OF    ELECTROLYTIC    COPPER-REFINING 

WORKS 56-147 

(A)  United  States:    i.  Raritan  Copper  Works,  56.    2.  Gug- 
genheim Refinery  (Perth  Amboy  Plant),   80.      '3.   Anaconda 
Electrolytic    Copper  Refinery,  89.      4.  Nichols  Refinery,  99. 
5.  Baltimore  Copper  Works,  100.    6.  Great  Falls  Refinery,  103. 
7.  Balbach  Refinery,  107.    8.  De  Lamar  Refining  Works,  no. 
9.  Buffalo  Refinery,  in.    10.  Blue  Island  Refinery,  113. 

(B)  Great  Britain:    i.  Bolton's  Froghall  Refining  Works, 
113.     2.  Pembrey   Copper   Works,    115.    3.   Bolton's  Widnes 
Refinery,  115.      4.  Leeds  Copper  Works.  116.      5.  Vivian  Re- 
finery, 123.     6.  McKechnie's  Refinery,  124. 

(C)  Germany:    i.   Hamburg  Refinery,    124.      2.   Mansfeld 
Copper  Works,  125.    3.  Oker  Refinery,  126.  4.  Goslar  Refinery, 

vii 


viii  CONTENTS. 


128.  5.  Schladern  Electrolytic  Works,  130.  6.  Niedermarsberg 
Refinery,  131.  7.  Altenau  Electrolytic  Works,  132.  8.  Burbach 
Refinery,  132.  9.  Papenburg  Electrolytic  Works,  132. 

(D)  Austria-Hungary:    i.   Witkowitz  Refinery,   133.       2. 
Brixlegg  Refinery,  135. 

(E)  France:    i.  Dives  Electrolytic  Works,  135.     2.  Biache 
Refinery,  136.     3.  Pont  de  Cheruy  Refinery,  136.    4.  Marseilles 
Electrolytic  Works,  137. 

(F)  Russia:    i.  Kalakent  Copper  Works,  137.    2.  Nikola jev 
Refinery,  147. 

CHAPTER  III. 

COST  ESTIMATES  OF  AN  AMERICAN  ELECTROLYTIC  COPPER  AND 
NICKEL  REFINERY,  WITH  GENERAL  PLAN  AND  DETAIL  DRAW- 
INGS  148-160 

Description  and  Specifications,  148.  Estimate  of  Costs  of 
Plant,  Stock,  and  Operating,  150.  General  Expenditures,  151. 
Cost  of  Office  Building,  151.  Cost  of  Power-house,  151.  Cost 
of  Tank-house,  152.  Cost  of  Furnace  Building,  152.  Cost  of 
Separating-house  and  Nickel  Refinery,  154.  Cost  of  Crystal- 
lizing-house,  158.  Cost  of  Silver  Refinery,  158.  Operating 
Costs  and  Profit,  159. 

APPENDIX. 

CHRONOLOGICAL  LIST  OF  PATENTS,  BOOKS,  AND  SPECIAL  ARTICLES 
ON  ELECTROLYTIC  COPPER-REFINING  METHODS  AND  APPA- 
RATUS   161-165, 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


CHAPTER  I. 

DEVELOPMENT,    METHODS,  AND    APPARATUS    OF    ELEC- 
TROLYTIC COPPER    REFINING. 

Historical  Data.  —  The  art  of  electrolytically  refining 
crude  copper  is  based,  like  the  allied  art  of  copper  plating, 
upon  various  discoveries  chiefly  made  between  the  years 
1800  and  1867,  the  date  of  the  introduction  of  the  dynamo. 

Although  more  than  thirteen  hundred  years  ago  Zosimus 
mentioned  the  earliest  known  fact  respecting  the  electro 
lytic  separation  of  metals,  viz.,  that  by  immersing  a  piece 
of  iron  in  a  cuprous  solution  it  acquired  a  coating  of  copper, 
it  was  first  definitely  shown  in  1800  that  copper  could  be 
deposited  from  solution  by  electric  currents,  which  fact 
was  demonstrated  by  Cruikshank. 

After  the  discoveries  of  magneto-electricity  by  Faraday 
in  1831  and  of  electrotyping  in  1838  by  Jacobi,  the  greater 
possibilities  of  the  application  of  electricity  to  metal 
deposition  began  to  be  recognized,  but  not  until  Elking- 
ton's  discovery  of  the  art  of  refining  copper  in  1865  and 
the  introduction  of  the  dynamo  in  1867  was  its  com- 
mercial future  assured.  Since  that  time  the  remarkable 
growth  of  electric  copper  refining  is  scarcely  paralleled  in 
the  history  of  any  other  industry. 


3  MODERN  ELECTROLYTIC  COPPER  REFINING. 

It  was  nearly  thirty-eight  years  ago  that  James  Elkington, 
the  English  silver-plater,  invented  the  commercial  electro- 
lytic method  of  refining  crude  copper,  and  in  1869  that  he 
founded  the  first  custom  plant  using  this  process,  at  Pem- 
brey,  Wales.  The  works  established  by  the  father  of 
modern  copper  refining  are  to-day  in  successful  operation, 
due  chiefly  to  the  remarkable  fact  that  both  Elkington 's 
process  and  apparatus  were  well  conceived  and  needed  but 
little  improvement  to  bring  them  up  to  present  standards. 
However,  it  was  not  until  the  last  two  decades,  when  the 
spread  of  electric  lighting  led  to  an  enormous  demand  for 
pure  copper,  and  the  perfection  of  the  dynamo  made  pos- 
sible the  cheap  generation  of  current,  that  the  great  im- 
portance of  Elkington 's  invention  was  fully  realized. 

In  Germany,  according  to  Schnabel,  the  first  electro- 
lytic refining  plant  erected  was  the  Hamburg  refinery 
(Norddeutsche  Affinerie),  built  in  .the  late  seventies  un- 
der Wohlwill's  management  and  operated  with  Gramme 
machines.  Subsequently  the  Oker  refinery  (Communion 
Huettenwerk) ,  in  which  Siemens  machines  were  used  to 
generate  current,  was  erected  under  Braeuning's  manage- 
ment, and  in  still  more  recent  years,  according  to  Schnabel, 
the  Mansfeld  Copper  Co.'s  electrolytic  plant  was  started. 

In  1879  an  experimental  plant  for  refining  copper  by 
electrolysis  was  operated  at  Phcenixville,  Pa.,  but  the  first 
commercial  refinery  in  the  United  States  was  built  by 
Edward  Balbach,  assisted  by  F.  A.  Thum,  at  Newark,  N.  J., 
in  1882-83.  The  refineries  at  Baltimore,  Md.,  and  at 
Anaconda  and  Great  Falls,  Mont.,  were  not  started  until 
1887,  1891,  and  1892,  respectively,  the  Raritan  Copper 
Works  in  1899,  and  the  De  Lamar  Works  and  the  new  Perth 
Amboy  electrolytic  plant  in  1902.  Sixteen  years  ago  the 
Balbach  and  the  Bridgeport  (Conn.)  works  were  the  only 
large  electrolytic  plants  in  America,  and  their  total  output 
was  less  than  24  tons  per  diem.  Yet  to-day  there  are  in 


DEVELOPMENT,   METHODS,   AND  APPARATUS.  3 

operation  ten  electrolytic  refineries,  producing  the  enor- 
mous quantity  of  764  tons  daily,  or  nearly  two  hundred 
and  seventy-nine  thousand  short  tons  of  copper  annually, 
besides  over  twenty-seven  million  ounces  of  silver  and  three 
hundred  and  forty-six  thousand  ounces  of  gold.  Thus 
over  80%  of  all  the  copper  produced  in  the  United  States 
is  now  refined  in  the  electrolytic  bath,  and  probably  nearly 
70%  of  the  entire  production  of  the  world  is  now  turned 
out  as  electrolytic  metal. 

Cost  of  Producing  Electrolytic  Copper. — Still  more  aston- 
ishing than  the  above  figures  of  output  is  a  comparison  of 
the  cost  of  producing  electrolytic  from  crude  copper  ten 
years  ago  with  the  cost  to-day.  Then  it  was  about  $20 
per  ton,  although  refiners  charged  $40  and  allowed  only 
92 \%  on  the  commercial  value  of  the  silver  in  the  Bessemer 
or  blister  copper.  Now  the  cost  of  refining  98%  copper 
anodes  at  several  of  the  large  works  in  the  United  States 
has  actually  been  lowered  to  $4  or  $5  per  ton,  it  appears, 
and  occasionally  contracts  for  refining  from  anode  to 
cathode  have  been  closed,  I  believe,  for  as  low  as  $7.50. 
The  chief  cause  of  the  great  reduction  in  the  cost  of  refining 
is  economy  in  utilizing  power  and  in  handling  material. 

Definitions  and  General  Principles. — The  following  defi- 
nitions from  Edward  Keller's  excellent  article  in  Mineral 
Industry,  vol.  vii,  are  reproduced  chiefly  in  order  to  give 
students  a  clear  conception  of  the  elementary  principles 
that  underlie  the  practical  working  of  the  electrolytic 
refining  process,  and  thus  make  the  subsequent  treatment 
of  the  subject  more  comprehensive : 

"Wherever  there  is  any  work  done  by  means  of  electricity 
there  are  three  governing  factors,  i.e.,  the  electromotive 
force,  the  resistance,  and  the  electrical  current.  The  elec- 
tromotive force  is  measured  in  volts,  and  is  technically 
spoken  of  as  voltage.  The  resistance  is  measured  in  ohms; 
the  current  in  amperes,  and  it  is  spoken  of  as  having  a 


4  MODERN  ELECTROLYTIC  COPPER  REFINING. 

certain  amperage.  The  relations  that  exist  between  these 
factors  are  expressed  in  Ohm's  law,  upon  which  and  the 
simple  deductions  therefrom  are  based  nearly  all  calcula- 
tions in  electrolytic  work. 

"Ohm's  law,  briefly  stated,  is  this:  "The  resulting  elec- 
trical current  is  equal  to  the  electromotive  force  divided 
by  the  resistance."  In  other  words,  the  electromotive 
force  (electrical  pressure  created  by  the  dynamo)  causes 
the  flow  of  the  electrical  current.  The  latter  is  directly 
proportional  to  the  former.  The  resistance  opposes  the 
flow  of  the  current.  The  latter  is,  therefore,  inversely  pro- 
portional to  the  former.  The  electrical  power  is  the  product 
of  the  number  of  volts  multiplied  by  the  number  of  amperes 
of  the  current.  Its  unit  is  called  a  watt. 

"From  Ohm's  law  it  follows  that  to  double  the  resistance 
halves  the  current,  the  electromotive  force  remaining  con- 
stant. Or  if  with  the  doubled  resistance  the  current  is  to 
remain  constant,  the  electromotive  force,  and  therewith 
the  power,  must  be  doubled.  This  applied  to  electrolysis 
means  that  with  the  same  current  we  can  deposit  an  infinite 
quantity  of  copper,  but  that  the  power  necessary  must 
ever  increase  proportionally  to  the  resistance. 

"Another  important  deduction  from  Ohm's  law  is  the 
following:  When  through  a  given  resistance  the  current  is. 
required  to  be  doubled,  the  power  must  be  increased  four 
times ;  or  in  general,  the  resistance  remaining  constant  the: 
power  increases  proportionally  to  the  square  of  the  current. 
This  applied  to  a  practical  example  means  that  if  from  a 
given  number  of  depositing  tanks  we  wish  to  double  the 
output  of  copper  by  doubling  the  current,  we  must  increase 
our  power  four  times ;  or  should  we  wish  to  quadruple  the 
output  the  power  must  be  increased  sixteen  times.  We 
therefore  encounter  the  economic  problem:  Is  it  more 
advantageous  to  double,  quadruple,  etc.,  the  capacity  of 
an  electrolytic  plant  as  to  number  of  tanks  or  to  increase 


DEVELOPMENT,   METHODS,   AMD  APPARATUS.  5 

four  times,  sixteen  times,  etc.,  the  power  in  order  to  in- 
crease the  output  proportionally  to  the  former?  The  first 
is  a  single  investment,  the  second  a  permanent  expense. 

"The  most  important  laws  in  direct  relation  to  electrolysis 
are  those  of  Faraday,  who  showed  that  a  given  quantity 
of  current  will  always  deposit  the  same  quantity  of  a  given 
element,  and  that  the  elements  are  deposited,  or  their 
compounds  decomposed,  proportionally  to  their  equiva- 
lent weights,  e.g.,  hydrogen  i,  oxygen  8,  copper  31.7,  sil- 
ver 1 08,  etc. 

"It  has  been  demonstrated  by  careful  experiment  that 
one  ampere  of  current  will  deposit  1.18656  g.  of  copper  in 
one  hour,  which  can  be  translated  for  technical  purposes 
to  mean  that  one  ampere  of  current  should  deposit  i  oz. 
of  copper  in  24  hours.  It  is,  therefore,  an  easy  matter  to 
keep  a  record  of  the  efficiency  of  a  plant,  or  to  detect  leak- 
ages of  the  current,  by  measuring  the  current,  weighing 
the  deposited  copper,  and  comparing  the  latter  with  the 
theoretical  quantity  required.  The  quantity  of  current, 
i.e.  the  number  of  amperes,  flowing  through  a  certain  unit- 
surface  is  termed  the  density  or  intensity  of  the  current. 
The  greater  the  density  of  the  current  the  greater  will  be 
the  rate  of  deposition  of  the  metal  on  a  given  surface.  In 
order  to  deposit  pure  copper  it  is  essential  to  have  a  con- 
stant current  density.  The  copper  is,  however,  deposited  in 
satisfactory  condition  only  when  the  current  density  is  main- 
tained within  certain  limits.  The  usual  density  employed 
in  the  United  States  is  10  or  12  amperes  per  square  foot.* 

"Joule  found  that  an  electrical  current  passing  through 
a  conductor  generates  a  certain  quantity  of  heat,  and  he 
established  what  is  known  as  Joule's  law,  namely,  the 
quantity  of  heat  developed  in  a  conductor  is  proportional 
to  the  resistance  of  that  conductor  and  to  the  square  of 
the  current  density.  When  heat  is  thus  produced  in  the 
conductors  and  the  electrolyte  it  is  a  waste  of  power. 

*  Now  12  to  15  amperes. — Note  by  Author. 


6  MODERN  ELECTROLYTIC  COPPER  REFINING. 

"  The  copper  plate  in  the  depositing  tank  which  receives 
the  current,  and  is  dissolved  by  the  latter 's  action,  is  called 
the  anode  plate.  The  plate  on  which  the  deposition  of  the 
metal  takes  place  is  called  the  cathode  plate,  and  the  two 
are  the  electrodes.  The  solution  in  which  they  are  im- 
mersed is  the  electrolyte. 

"  In  an  electrolytic  copper  refinery  the  current  must  be 
adapted  to  the  given  condition  of  electrodes  and  tank 
arrangement,  or  the  latter  to  a  given  current.  For  exam- 
ple, if  with  a  given  current,  say  1000  amperes,  we  wish  a 
current  density  of  10  amperes  per  square  foot  of  anode  sur- 
face, and  our  anode  plates  have  a  surface  of  10  sq.  ft.,  it 
is  necessary  to  let  the  current  pass  through  10  such  plates 
connected  in  multiple.  These  would  be  placed  in  one  tank 
with,  say,  n  cathode  plates,  through  which  the  current 
would  pass  into  another  tank  of  the  same  description,  and 
so  on.  Tanks  are  thus  connected  in  series.  As  their  num- 
ber increases,  the  voltage  necessary  to  carry  the  current 
through  them  must  increase  proportionally.  With  the 
increase  of  voltage  the  danger  of  loss  of  current  through 
leakage  increases.  There  must,  therefore,  be  a  limit  to 
the  number  of  tanks  connected  in  series.  The  highest 
voltage  in  present  practice  is  about  180. 

"  The  lower  limit  of  a  series  is,  of  course,  a  single  couple, 
one  anode,  and  one  cathode,  with  an  electrical  pressure  of 
a  fraction  of  one  volt,  the  exact  value  depending  on  the 
distance  between  the  electrodes,  the  density  of  the  current,, 
the  character  of  the  electrolyte,  and  the  composition  of  the 
anode.  In  actual  practice  the  voltage  between  plates, 
varies  between  about  \  and  J-  volt,  according  to  the  system 
employed.  The  voltage  necessary  to  decompose  copper 
sulphate  and  to  deposit  the  metal  on  the  cathode  is  theo- 
retically 1. 1 6  volt.  With  a  soluble  anode  this  is  counter- 
balanced by  the  energy  evolved  in  the  formation  of  copper 
sulphate  on  the  anode  surface." 


DEVELOPMENT,   METHODS,   AND  APPARATUS. 


Comparison  of  Methods. — There  are  only  two  systems 
of  electrolytic  copper  refining  proper  now  in  use,  which 
differ  chiefly  in  the  mode  of  arranging  the  electrodes.  They 


FIG.  1 


FIG.  2 


FIG.  3 


MULTIPLE 

FIG.  4 


s 


RANDOLPH 


FIG.  5 


STALMANN 


ANODE 
CATHODE 


SCREEN 


Arrangement  of  Electrodes  in  the  Different  Systems  of  Refining. 
FIG.  6  FIG.  7 


FIG.  8 


Various  Arrangements  of  Conductors  in  the  Multiple  System. 

(The  dotted  lines  indicate  the  outlines  of  the  tanks.) 

are  known  as  the  multiple  and  the  series  processes,  the 
latter  being  employed  in  only  two  or  three  works,  and  the 
use  of  the  Smith,  Stalmann,  and  Randolph  arrangements 
of  electrodes  having  been  discontinued.  The  scheme  of 


8  MODERN  ELECTROLYTIC  COPPER  REFINING. 

arrangement  of  electrodes  and  conductors  in  these  various 
systems  is  indicated  in  the  subjoined  cuts,  Figs,  i  to  8,  in- 
clusive, from  which  it  will  readily  be  gathered  that  vertical 
electrodes  are  employed  in  the  Multiple,  Hayden,  and  Stal- 
mann  processes,  and  horizontal  electrodes  in  the  Randolph 
and  Smith  systems,  and  that  the  latter  is  the  only  one  in 
which  screens  to  prevent  the  anode  slimes  from  falling  on 
the  depositing  copper  are  interposed  between  the  plates. 
A  few  other  processes,  such  as  the  Elmore,  Emerson,  and 
Cowper-Coles  methods  for  producing  tubes  and  other 
shapes,  and  Thofehrn's  direct  method  of  producing  wire 
bars,  are  more  properly  shape -producing  than  true  refining 
processes,  and  will  therefore  not  be  treated  in  this  mono- 
graph, excepting  in  so  far  as  they  have  attained  practical 
prominence  in  copper  refining.  Neither  will  I  discuss  the 
Marchese,  Hoepfner,  Siemens  and  Halske,  and  Keith 
processes,  as  they  apply  particularly  to  ores  and  matte  and 
not  to  crude  copper,  and  have  not,  it  appears,  proven 
profitable. 

Those  who  have  to  select  a  refining  process  and  have 
to  operate  electrolytic  works,  must  consider  the  following 
facts  in  comparing  the  two  systems  of  refining: 

The  series  or  Hayden  system,  as  developed  in  the  United 
States,  differs  from  the  commonly  employed  multiple 
system  in  the  following  respects: 

1.  Special  cathodes,  as  in  the  multiple  system,  are  not 
necessary,  one  side  of  the  anode  plate  serving  as  cathode. 

2.  The  anodes,  excepting  the  first  and  last,  are  not  con- 
nected to  copper  conductors,  the  solution  alone  serving  to 
conduct  the  current,  and  the  plates  are  placed  in  series. 

3.  Much  larger  tanks  than  those  used  in  the  multiple 
system    are    employed,    the    size    at    the    Nichols    Works, 
Brooklyn,  being  16  ft.  long,  5  ft.  deep,  and  5^  ft.  wide. 

4.  The  anodes  used  are  either  }  or  f  in.  thick  and  are 
longer,  thinner,  and  narrower  than  multiple  anodes.     They 


DEVELOPMENT,  METHODS,   AND  APPARATUS.  ,   9 

are  straightened  by  rolling  at  the  Baltimore  Hayden  plant 
and  hammered  straight  by  hand  at  the  refinery  of  the 
Nichols  Company.  At  the  latter  works  six  anodes,  each 
4.5  ft.  long,  10  in.  wide,  and  weighing  65  Ibs.,  are  suspended 
abreast  in  a  tank  and  form  a  row,  while  at  the  Baltimore 
Copper  Works  a  row  is  made  tip  of  two  anodes,  a  lower  and 
an  upper  plate,  held  at  each  side  in  a  grooved  slide.  The 
rows  of  anodes  are  placed  0.5  in.  apart  at  Baltimore  and 
0.8  to  0.9  in.  apart  at  the  Nichols  plant,  and  the  drop  in 
potential  between  any  two  rows  is  therefore  as  low  as 
one-ninth  of  a  volt. 

The  series  system  is  used  only  by  the  Baltimore  Electric 
Refining  Company  and  the  Nichols  Chemical  Company,  a 
serious  drawback  being  found  in  the  large  quantity  of  scrap 
copper  produced  with  this  process,  which  averages  about 
twice  as  much  as  in  the  multiple  process. 

With  the  same  solution,  it  is  obvious  that  the  voltage 
required  per  tank  will  depend  upon  the  area  of  the  plates, 
the  distance  of  the  plates  apart,  and  the  number  of  plates 
in  series.  In  a  series  tanjc,  therefore,  the  electromotive 
force  must  be  many  times  greater  than  the  electromotive 
force  required  in  a  multiple  tank;  and  where  many  plates 
are  arranged  in  series,  the  voltage  required  to  maintain  a 
given  density  of  current  is  very  great  and  leads  to  short- 
circuiting  and  other  evil  consequences,  unless  great  care 
is  constantly  exercised. 

As  Barnett  states  in  Peters'  "Modern  Copper  Smelt- 
ing," one  must  also  take  into  account  that  the  slimes,  as 
they  collect  on  the  bottom  of  the  tank,  form  a  large  con- 
ducting plate.  If  the  electromotive  force  is  sufficient  to 
overcome  the  resistance  between  the  bottom  of  the  elec- 
trodes and  the  layer  of  slimes,  the  current  will  flow  partly 
through  the  electrodes  and  partly  through  the  slimes,  in 
amounts  inversely  as  the  resistance  of  the .  two  routes. 
Owing  to  the  lessened  density  of  current  at  the  electrodes 


10  MODERN  ELECTROLYTIC  COPPER  REFINING. 

this  will  be  manifest  in  a  diminished  output  per  tank. 
That  such  short-circuiting  occurs  is  proved  by  the  fact  that 
more  copper  is  deposited  on  the  end  electrodes  in  the  series 
than  on  the  intermediate  plates,  for  there  the  currents  will 
recombine  to  a  greater  density  per  square  foot  of  deposit- 
ing surface  than  elsewhere  in  the  tank.  Likewise  the 
observed  rapid  concentration  of  copper  in  the  electrolyte 
of  series  processes  is  probably  largely  due  to  the  combined 
chemical  and  electrolytic  solution  of  the  anode  scrap  in 
the  slimes. 

Series  tanks  are  constructed  of  slate,  or  of  wood,  lined 
with  some  acid-proof  non-conductor,  as  a  lead  lining  mani- 
festly could  not  be  employed  in  the  series  system.  Slate 
tanks,  although  durable,  are  very  expensive,  as  the  average 
cost  of  slate  for  electrolytic  vats  in  the  United  States  is 
about  40  cents  per  square  foot  of  i  J  in.  thickness  in  lengths 
not  over  5  ft. ;  but  the  cost  advances  at  the  rate  of  5  cents 
per  square  foot  for  every  additional  foot  in  length. 

Wooden  tanks,  although  cheap  (they  usually  cost  about. 
$30  each),  soon  become  efficient  conductors  and  lose  con- 
siderable current  by  short  circuits  around  the  sides  of  the 
tanks  and  leakage  to  the  ground.  This  is  partly  because 
the  penetration  of  the  acid  sulphate  of  copper  cannot  well' 
be  prevented  in  tanks  constructed  of  wood,  even  if  lined 
with  tarred  felt  and  asphalted.  The  older  the  tanks  the 
more  subject  are  they  to  these  disorders.  That  is  one  of 
the  reasons  why,  in  the  series  system,  only  about  90%  of 
the  theoretical  deposit  is  obtained  from  a  given  current, 
even  with  comparatively  new  wooden  tanks,  and  that  the 
average  efficiency  falls  far  below  this  figure. 

In  two  given  plants  having  equal  cathode  surfaces 
and  using  equal  current  densities  the  multiple  system 
requires  only  about  one-half  the  anode  copper  used  in  the 
series  system.  As  refineries  tie  up  between  several  hundred 
and  several  thousand  tons  of  copper  each,  the  factor  of 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  II 

interest  on  one-half  of  this  is  not  to  be  disregarded.  In 
series  processes,  therefore,  the  anodes  are  made  thin,  so 
as  to  obtain  the  maximum  depositing  surf  ace  with  minimum, 
weight  of  anodes.  But  the  greater  care  which  must  be 
exercised  in  preparing  thinner  anodes,  and  the  need  of 
more  frequently  renewing  such  anodes  than  the  thicker 
anodes  used  in  the  multiple  system,  entail  fixed  charges 
which  about  balance  the  saving  in  interest  effected  by 
using  the  thinner  electrodes. 

Maurice  Barnett  ably  reviews  the  question  of  the 
relative  expense  of  operating  the  two  systems  of  refining 
in  Peters'  "Modern  Copper  Smelting,"  and  reaches  the 
following  conclusion: 

* '  In  order  to  compensate  for  the  extra  copper  used  in 
the  series  system,  it  is  the  rule  to  economize  in  tanks  and 
solution  by  arranging  the  electrodes  closer  together  than 
is  done  in  the  multiple  system.  With  electrodes  close 
together  there  is  the  possibility  of  sprouting  and  short- 
circuiting,  unless  the  current  is  maintained  of  uniform 
density  over  the  entire  surface  of  the  electrodes.  Hence 
arises  the  necessity,  in  series  processes,  of  working  the 
anode  copper  up  to  a  point  where  it  is  uniform  and  follow- 
ing this  by  poling.- 

"In  the  multiple  system  the  copper  does  not  neces- 
sarily have  to  be  improved  and  poled,  although  this  pro- 
cedure is  not  uncommon.  At  the  Boston  and  Montana 
Company's  Works  at  Great  Falls,  Mont.,  the  anodes  are 
cast  direct  from  the  converters,  thus  saving  the  entire  cost 
of  remelting  and  refining  the  anode  copper  inherent  in  the 
series  system.  To  neutralize  the  inevitable  consequence 
of  unequal  corrosion  following  from  such  a  procedure,  it 
1  is  customary  to  place  the  electrodes  from  two  to  two  and 
one -half  inches  apart.  There  is  not  then  the  necessity  for 
maintaining  a  uniform  density  of  current  over  the  entire 
surface,  this  inequality  of  density  in  the  rougher  plates 


12  MODERN  ELECTROLYTIC  COPPER  REFINING. 

being  overcome  by  changing  the  cathodes  rather  more 
frequently  than  the  anodes.  Short-circuiting  from  sprout- 
ing is  thus  prevented  and  the  inequality  of  density  of  cur- 
rent neutralized.  In  the  series  system,  'stripping'  the 
deposit  cannot  be  economically  practiced  until  the  tank, 
as  a  whole,  is  ready  to  be  emptied. 

' '  Of  course  the  use  of  less  pure  copper  in  the  anodes 
in  the  multiple  system  tends  to  make  the  electrolyte  impure 
and  increase  the  cost  of  refining  by  necessitating  renewals 
of  the  electrolyte.  This  is  true,  however,  only  where  no 
effort  is  made  to  keep  the  electrolyte  free  from  the  im- 
purities that  enter  it  from  the  anodes.  At  first  sight  it 
would  appear  as  if  the  extra  expense  in  preparing  the 
anodes  would  be  justified,  because  smoother  and  thinner 
electrodes  can  be  brought  closer  together — say  to  one- 
half  the  usual  distance  allowed  in  the  multiple  system, 
resulting  in  a  reduction  of  the  resistance  between  electrodes 
and  a  doubling  of  the  output  per  horse-power  of  mechanical 
energy  expended. 

"While  the  output  is  undoubtedly  increased  in  this 
way,  it  cannot  at  best  be  more  than  double  the  output 
under  the  multiple  system  save  where  the  anodes  are  rolled 
plates.  Here  the  resistance  between  electrodes  is  as  low 
as  one-third  that  between  electrodes  in  a  multiple  tank. 
The  expense,  however,  of  rolling  the  plates  and  the  greater 
cost  of  stripping  indicate  that  economv  cannot  be  effected 
along  these  lines. 

* '  In  a  general  way  it  may  be  stated  that  the  cost  of 
improving  and  poling  anode  material  exceeds  the  saving 
resulting  from  increased  output  per  horse -power  of  mechan- 
ical energy  expended.  The  multiple  system,  moreover,  is 
free  from  the  costly  process  of  stripping  the  deposited  cop- 
per from  the  anode  scrap.  This  separation  is  frequently 
so  difficult  a  matter  that  the  deposited  plate  is  often  thrown 
back  into  the  blister  furnace  along  with  the  rest  of  the  scrap. 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  13 

"Furthermore,  the  cost  of  maintenance  of  plant  is 
greater  in  the  series  process,  owing  to  the  fact  that  the  life 
of  the  tanks,  when  made  of  wood,  is  limited  to  about  four 
years.  Series  arrangements  gain  slightly  from  the  circum- 
stance that  there  is  less  loss  of  energy  in  the  conductors 
than  in  the  multiple  system,  where  there  is  always  a  con- 
sumption of  about  5%  to  8%  of  the  mechanical  energy 
of  the  circuit.  Where  coal  is  cheap,  this  is  not  very  im- 
portant. The  interest  charges  on  the  plant  are  also  slightly 
in  favor  of  the  series  system.  This  favorable  factor  of  the 
latter  is  offset  by  heavier  cost  of  renewals  and  larger  interest 
on  stock.  The  series  system  is  free  from  the  expense  of 
making  cathodes,  inherent  in  the  multiple  system,  but  is 
still  subject  to  heavy  charges  for  stripping,  amounting  to 
four  times  that  of  making  cathodes. 

' '  Balancing  these  various  factors  as  well  as  is  possible 
in  two  works  operating  under  the  same  conditions  of  cost 
of  labor  and  fuel,  there  is  a  saving  in  the  operating  ex- 
penses, in  using  the  multiple  system,  of  nearly  $2  per  ton 
of  refined  copper.  This  difference  is  susceptible  of  greater 
increase  if  the  refinery  is  run  as  part  of  a  converting  estab- 
lishment; for  since  anodes  may  be  made  direct  from  the 
converters,  the  expense  of  making  them  in  the  reverber- 
atory,  amounting  to  from  $2  to  $3.40  per  ton,  is  altogether 
avoided. 

"In  general,  the  greater  first  cost  of  works  using  the 
multiple  system  lies  in  the  extra  expense  of  the  tank  con- 
ductors and  plates  for  making  cathodes  plus  about  one- 
half  of  the  value  of  the  lead  lining  of  multiple  tanks  plus 
one-third  of  the  value  of  the  steam  and  power  plants.  How- 
ever, in  spite  of  its  larger  first  cost,  the  multiple  system  is, 
undoubtedly,  susceptible  of  greater  economy  than  is  pos- 
sible under  series  arrangements,  as  is  shown  by  its  adop- 
tion, after  costly  and  exhaustive  experiments,  in  works 
where  the  series  system  was  formerly  used. 


14  MODERN  ELECTROLYTIC  COPPER  REFINING. 

"To  sum  up  the  preceding  points,  the  current  effi- 
ciency of  the  multiple  process  averages  95%  as  against 
90%  for  the  series  process  under  similar  conditions;  much 
less  copper  is  held  back  in  the  multiple  than  in  the  series 
system,  and  the  relative  cost  of  operating  it  is  probably 
.less  by  nearly  $2  per  ton. ' ' 

Efficiency  of  Refining  Plants. — Attention  should  be 
^called  to  an  important  point  sometimes  overlooked  by 
refiners,  namely,  their  frequent  waste  of  power,  or  the  low 
^energy  efficiency  of  certain  copper  works.  While  the  cur- 
rent efficiency  of  these  same  works,  or  quotient  of  the 
amperage  employed  for  a  given  output  divided  by  the 
theoretical  amperage  required  to  deposit  the  same  amount 
of  copper,  may  be  as  high  as  90%  or  95%,  their  energy 
efficiency,  or  quotient  obtained  by  dividing  the  energy  or 
current  consumed  in  doing  useful  work  by  the  total  energy 
furnished  by  the  dynamo,  is  sometimes  only  30%,  and  in 
the  average  refinery  it  does  not  often  exceed  65%. 

The  loss  of  energy  is  due  partly  to  bad  metal  contacts 
and  short-circuiting  and  partly  to  the  use  of  voltages  much 
in  excess  of  those  actually  required  to  overcome  the  resist- 
ance of  the  solution  and  of  the  metal  conductors.  These 
facts  show  how  important  it  is  in  electrolytic  refining  to 
exercise  close  supervision,  and  how  its  absence  is  often 
paid  for  in  heavy  waste  of  energy  or  by  its  equivalent 
value  in  coal  or  money. 

Stock  of  Metal  in  Refining. — It  is  interesting  to  note 
the  great  reduction  in  recent  years  of  the  stock  of  metal 
required  in  copper  refineries  per  unit  of  output. 

Recognizing  the  disadvantageous  features  of  the  elec- 
trolytic process  of  refining  copper  to  be,  i,  the  large  cost 
of  plant;  2,  the  constant  attention  required  to  be  paid 
to  the  process;  3,  the  comparatively  large  amount  of 
covered  space  necessary;  and  4,  the  continuous  period 
of  time  during  which  a  considerable  stock  of  metal  remains 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  15 

unproductive  of  interest,  refiners  turned  their  attention 
chiefly  toward  the  last  as  offering  the  greatest  field  for 
improvement.  Their  efforts  in  this  direction  have  been 
eminently  successful,  especially  in  the  United  States. 

Fifteen  years  ago  it  was  not  at  all  uncommon  for  copper 
refineries  here  and  abroad  to  require  75  to  100  times  as 
much  copper  as  was  daily  produced  in  their  electrolytic 
plants  to  stock  their  tanks  for  regular  work.  Subsequently 
improvements  of  various  kinds  brought  this  amount  down 
to  50  or  60  tons  for  every  ton  of  copper  produced;  yet 
to-day,  in  several  cases,  only  15  to  20  tons  are  required 
per  i  ton  of  output. 

This  great  improvement,  which  has  so  largely  reduced 
the  cost  of  copper  refining,  is  due  chiefly  to  the  employ- 
ment of  an  increased  density  of  current,  resulting  in  more 
rapid  working  and  a  greater  output  with  the  same  stock 
of  copper  and  solution.  Formerly  current  densities  of  2 
to  4  amperes  per  square  foot  of  cathode  surface  were  com- 
monly used  in  refining;  yet  to-day  they  average  from  12  to 
1 6  amperes  in  the  United  States,  and  in  one  or  two  works 
current  densities  of  as  much  as  35  or  40  amperes  are  em- 
ployed. The  quantity  of  copper  undergoing  treatment 
with  the  same  output  of  metal  is  thus  correspondingly 
reduced  to  one-fourth,  and  in  some  cases  less  than  one-fifth, 
of  what  it  was  formerly.  One  must  not  overlook  the  fact, 
however,  that  there  are  important  limiting  factors  to  this 
tendency  to  increase  the  current  strength  and  thereby 
reduce  the  stock  required.  In  the  first  place,  the  maxi- 
mum allowable  flow  of  current  and  the  minimum  permissi- 
ble rate  of  circulation  and  speed  of  purification  depends  on 
the  richness  of  the  anode  in  precious  metals  and  on  its 
contents  and  that  of  the  solution  in  arsenic  and  other  im- 
purities. If  large  quantities  of  these  are  present,  a  high- 
current  density,  which  is  of  course  accompanied  by  a  high 
rate  of  anode  dissolution  and  an  impure  electrolyte,  would 


1 6  MODERN  ELECTROLYTIC  COPPER  REFINING. 

carry  part  of  the  silver  and  arsenic  to  the  depositing  copper, 
chemically  or  mechanically,  and  thus  reduce  its  purity  and 
its  electric  conductivity,  if  special  means  or  prevention  are 
not  adopted.  With  very  pure  crude  copper,  on  the  other 
hand,  current  densities  as  high  as  30  and  even  40  amperes 
may  be  used. 

In  refining  plants  treating  arseniferous  copper  bullion 
rich  in  precious  metals,  the  average  electric  current  is  not 
over  8  to  10  amperes  per  square  foot  (counting  both  sides, 
of  the  cathode  plate),  while  those  producing  electrolytic 
copper  from  a  good  or  extra  good  quality  of  copper  bullion 
may  employ  three  or  four  times  this  current  density. 

Under  modern  conditions,  a  1 5-ton  plant  does  not 
usually  require  stocks  of  more  than  200  to  300  tons  of 
copper  to  be  placed  in  course  of  treatment,  while  600  to  900 
tons  were  formerly  considered  necessary  for  a  daily  output 
of  15  tons.  With  plants  of  any  given  capacity  much 
smaller  tonnages  in  stock  are  considered  adequate  nowa- 
days than  in  former  times. 

Besides  the  total  stock  of  copper  in  the  tanks,  however, 
there  is  generally  tied  up  from  50%  to  100%  of  this  quan- 
tity in  the  form  of  blister  copper  for  making  anodes,  main 
conductors,  new  anodes  ready  for  immersion,  residues  of 
old  anodes,  solution  and  stock  of  refined  copper. 

It  appears  that  the  total  amount  of  copper  in  process 
of  treatment — stock,  solution,  and  conductors — averages  10 
to  20%  of  the  yearly  output  of  our  electrolytic  copper  works, 
as  against  a  permanent  stock  of  30%  to  40%  formerly. 

Other  things  being  equal,  this  means  a  great  reduction 
of  the  period  of  time  during  which  the  stock  of  metal  re^ 
mains  unproductive  of  interest,  or  an  equivalent  decrease 
in  the  amount  of  working  capital  required  for  a  given  out- 
put in  refining  copper. 

Sampling  and  Assaying. — -With  regard  to  the  sampling 
of- blister  copper  and  anodes,  E.  Keller  proposes  the  follow- 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  17 

ing  improvement:  It  has  been  found  that  samples  taken 
from  different  portions  of  anode  plates  and  pigs  of  blister 
copper  are  apt  to  vary  considerably  in  their  percentages 
of  gold  and  silver,  as  well  as  base  metals,  owing  to  their 
segregation  in  cooling,  and  that  the  common  method  of 
securing  samples  by  drilling,  punching,  or  chipping  often 
leads  to  erroneous  results.  A  more  rational  and  satisfac- 
tory mode  of  sampling  is  to  take  the  sample  when  the 
copper  is  in  the  furnace  and  after  the  charge  has  become 
thoroughly  mixed,  and  either  to  pour  a  shot  sample  from 
a  ladle  in  which  the  whole  metal  is  liquid  or  to  cast  a 
sample  plate  the  thickness  of  which  is  small  compared 
to  the  other  two  dimensions,  and  to  drill  or  punch  a  sample 
from  this  plate. 

With  electrolytic  copper,  not  only  different  plates  from 
the  same  tank,  but  different  portions  of  the  same  plate  may 
show  a  different  composition,  and  the  sampling  is  only 
satisfactory  after  the  cathode  plates  are  melted  down  and 
the  furnace  charge  has  become  thoroughly  mixed. 

Refiners  have  unfortunately  not  yet  agreed  upon  stand- 
ard methods  of  assaying  and  analyzing  blister  copper,  fur- 
nace slags,  anodes,  cathodes,  slimes,  and  refinery  solutions, 
and  to  describe  all  the  methods  in  use  at  the  various  plants 
here  would  require  more  space  than  I  have  now  at  disposal. 
The  reader  is  therefore  referred  to  descriptions  and  dis- 
cussions of  the  various  methods  that  have  appeared  in  the 
Engineering  and  Mining  Journal,  Dec.  16,  1899,  and  The 
Mineral  Industry,  vol.  ii,  pp.  276-277;  vol.  viii,  p.  187; 
vol.  ix,  pp.  226-229,  and  vol.  x,  p.  228. 

The  Chemistry  and  Physics  of  Refining. — Prof.  M.  Kiliani, 
in  1885,  was  the  first  investigator  to  call  attention  to  many 
of  the  following  chemical  and  electrochemical  reactions 
involved  in  copper  refining. 

With  a  normal  current  density  of  2  amperes  per  square 
loot  and  an  electrolyte  containing  150  g.  blue  vitriol  and 


1 8  MODERN  ELECTROLYTIC  COPPER  REFINING. 

50  g.  sulphuric  acid  per  liter,  the  cuprous  oxide  contained 
in  the  anode  because  of  its  poor  conductivity  remains 
unattacked  and  accumulates  in  the  anode  residue  or 
slimes.  By  a  secondary  reaction,  however,  it  gradually 
dissolves  and  thus  reduces  the  acidity  of  the  solution  and 
increases  the  copper  contents  of  the  latter. 

Silver,  gold,  and  platinum,  unless  present  in  considerable 
quantities,  and  unless  the  solution  is  not  of  normal  strength, 
are  completely  recovered  in  the  tank  residues,  barring 
0.2-0.3  oz.  Ag  per  ton  found  in  almost  all  cathode  copper. 
If  the  solution  becomes  neutral,  silver  is  dissolved  and  apt 
to  be  deposited  on  the  cathode.  The  solution  of  the  silver 
is  checked  by  the  addition  of  salt  or  a  small  beakerful 
(say  300  cc.)  of  hydrochloric  acid  to  the  contents  of  every 
electrolytic  tank. 

It  has  not  yet  been  definitely  settled  whether  the  arsenic 
in  the  anode  is  present  chiefly  as  metal  or  as  arsenate  of 
copper.  In  the  former  case  it  passes  into  solution  during 
electrolysis  as  arsenious  acid,  and  arsenic  is  not  deposited 
until  the  electrolyte  has  become  saturated  with  this  acid. 
When  arsenate  of  copper  is  found  in  the  anode,  this  salt, 
being  a  non-conductor  of  electricity,  is  not  altered  in  its 
composition,  and  forms  part  of  the  residue.  In  the  course 
of  time,  however,  arsenious  acid  is  dissolved  as  a  secondary 
result  of  the  action  of  the  free  sulphuric  acid  of  the  elec- 
trolyte, and  a  certain  amount  of  green,  insoluble,  slimy 
.arsenite  of  copper  is  eventually  formed.  This  secondary 
formation  of  arsenious  acid  can  be  diminished  by  frequently 
removing  the  slime  film  from  the  anodes,  i.e.,  lifting  the 
latter  out  of  the  tanks  and  washing  off  their  adhering  slimes 
into  a  special  receiver.  From  a  neutral  bath  or  a  solution 
containing  an  insufficiency  of  copper,  arsenic  is  deposited 
on  the  cathode  with  the  copper.  Some  American  refiners 
add  0.5%  and  others  up  to  20%  of  ammonium  sulphate  to 
the  electrolyte  to  hinder  as  much  as  possible  the  electro- 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  19 

deposition  of  arsenic  with  the  copper.  The  limit  of  arsenic 
allowed  in  the  cathode  copper  for  making  wire  bars  is 
understood  to  be  0.002%  at  the  Balbach  Works  and  o.ooi  % 
at  the  Nichols  Refinery. 

Antimony,  if  found  as  metal  in  the  anode,  partly  dis- 
solves at  first,  although  a  portion  of  this  dissolved  antimony 
may  eventually  precipitate  as  a  neutral  salt,  and  partly 
forms  an  insoluble  basic  sulphate  of  antimony,  which  coats 
the  anode.  In  the  course  of  time  antimonious  acid  is 
formed,  on  account  of  the  secondary  action  of  the  free  sul- 
phuric acid  present.  Antimony  is  not  electrolytically 
deposited  on  the  cathode  as  long  as  the  solution  is  nearly 
normal  in  composition  (containing  5%  to  6%  free  acid  and 
15%  to  20%  bluestone),  even  if  the  electrolyte  is  so  sat- 
urated with  antimony  that  its  basic  salts  begin  to  separate. 
At  the  worst  a  little  basic  antimony  compound  may  be 
mechanically  deposited  on  the  cathode  and  form  a  black 
coating  containing  both  copper  and  antimony.  Antimony 
is  apt  to  deposit  with  the  copper  and  cause  the  latter  to 
become  dull  colored,  brittle,  and  to  form  needle-like  pro- 
jections whenever  the  solution  becomes  neutral,  but  if 
the  solution  contains  an  insufficiency  of  copper,  antimony 
is  invariably  thrown  down  on  the  copper,  even  when  con- 
siderable free  acid  is  present. 

Iron  in  the  anode  dissolves  more  readily  than  the  copper 
and  forms  ferrous  sulphate,  which  in  time  is  partly  oxidized 
to  ferric  compounds.  These  are  produced  freely  and 
directly  whenever  the  density  of  the  current  reaches  1300 
amperes  per  square  meter.  "Sprouting"  of  the  cathode 
is  produced,  if  iron  is  allowed  to  replace  copper  in  the  elec- 
trolyte, until  there  is  but  2  g.  of  copper  present  to  the  liter 
of  solution. 

Copper  deposited  with  a  weak  current  from  a  neutral 
solution,  even  if  the  latter  is  free  from  impurities,  is  often 
so  brittle  that  it  can  be  readily  pulverized.  This  is  due 


20  MODERN  ELECTROLYTIC  COPPER  REFINING. 

to  the  fact  that  the  copper  contains  cuprous  oxide.  Of 
course  the  neutralization  of  the  electrolyte  also  decreases 
the  conductivity  of  the  solution,  so  that  its  resistance  with 
anodes  5  cm.  apart,  for  example,  may  be  raised  from,  say, 
o.i  volt  (normal)  to  0.25  volt.  A  weak  current  is  not  able 
to  completely  decompose  the  copper  sulphate  into  Cu  and 
SO4,  so  that  some  Cu2O  is  deposited  with  the  copper.  This 
deposit  of  Cu2O  decreases  with  increasing  current  strength 
up  to  that  point  at  which  the  current  is  strong  enough  to 
throw  down  absolutely  pure  copper. 

In  acid  solutions  the  cuprous  oxide  of  the  cathode  is 
decomposed  by  a  secondary  action,  while  in  a  neutral  elec- 
trolyte it  remains  on  the  cathode.  Roessler's  hypothesis 
may  explain  why  certain  refiners  associate  a  green  solution 
with  bad  cathode  copper,  good  copper  being  deposited 
from  the  same  solution,  as  soon  as  it  changes  its  color  from 
green  to  blue.  Roessler  believes  that  under  certain  con- 
ditions metallic  copper  reduces  an  acid  solution  of  cupric 
sulphate  and  forms  cuprous  sulphate,  which  is  subsequentlv 
oxidized  by  the  air  to  cupric  sulphate.  The  quantity  of 
copper  so  dissolved  increases  with  the  rapidity  of  the  cir- 
culation, i.e.,  the  more  the  electrolyte  is  exposed  to  the 
atmosphere,  and  with  the  diminution  of  the  density  of  the 
current.  The  more  thoroughly  the  circulation  is  kept  up, 
the  purer,  more  finely  crystalline,  and  more  flexible  will  be 
the  deposited  copper,  even  with  nearly  pure  solutions  and 
under  otherwise  normal  conditions. 

Tellurium  and  selenium,  which  are  frequently  present 
in  anode  copper,  probably  as  telluride  and  selenide  of  silver 
or  copper,  have  but  little  effect,  it  seems,  on  the  purity  of 
the  copper  deposited. 

It  is,  of  course,  very  important  that  the  acidity  of  the 
.electrolyte  be  determined  daily  and  that  the  normal  com- 
position of  the  electrolyte  be  maintained. 

.Since  the  time  of  the  appearance  of  Kiliani's  masterly 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  21 

essay,  the  accepted  views  of  some  of  the  reactions  involved 
in  electrolytic  refining  have  slightly  changed.  Credit  is  due 
Dr.  Emil  Wohlwill  for  his  recent  work  in  connection  with 
observations  of  such  reactions  and  their  explanation,  as 
given  in  the  late  revised  edition  of  Bore  her 's  "Elektro- 
Metallurgie, "  pp.  198-206.  Wohlwill  finds  that  Kiliani 
underrated  the  importance  of  the  presence  of  finely  divided 
metallic  copper  in  the  anode  residue.  Such  copper,  sepa- 
rating out  from  anodes  that  are  free  or  comparatively  free 
from  impurities,  appears  of  a  dark  reddish  or  rich  red  color 
as  long  as  discoloring  impurities  are  absent.  The  amount 
of  such  finely  divided  metallic  copper  (termed  anode  powder) 
produced  depends  chiefly  on  the  current  density  used,  and 
varies  according  to  the  following  principles :  i ,  the  less  the 
current  density  the  greater  the  quantity  of  powder  forming  in 
a  given  time ;  2 ,  with  the  same  current  density  the  amount 
produced  increases  with  an  increase  in  the  acidity  of  the 
electrolyte;  and  3,  under  otherwise  similar  conditions,  the 
quantity  of  anode  powder  formed  varies  inversely  as  the 
duration  of  uninterrupted  electrolysis. 

The  following  hypothesis  may  serve  to  explain  the  above 
phenomena.  During  electrolysis  a  small  amount  of  cuprous 
sulphate  forms  at  the  anode  along  with  the  cupric  sulphate, 
only  to  decompose  again  in  contact  with  the  anode  or  in 
its  immediate  vicinity  into  copper  and  cupric  sulphate, 
somewhat  as  copper,  dissolved  in  a  hot  solution  of  cupric 
sulphate,  separates  out  as  metal  when  the  solution  is 
refrigerated.  But  as  the  current  density  decreases,  the 
number  of  univalent  ions  forming  along  with  the  bivalent 
ions  increases,  and  consequently  the  greater  the  amount 
of  anode  powder  produced. 

In  Wohlwill 's  opinion,  the  separated  copper  powder  in 
contact  with  the  unattacked  copper  of  the  anode  acts  like 
an  electro-negative  or  less  soluble  metal  and  consequently 
protects  the  copper  surface  it  covers.  The  electrolytic 


22  MODERN  ELECTROLYTIC  COPPER  REFINING. 

action  is  thus  restricted  to  the  uncovered  portions  of  the 
anode  and  therefore  to  a  decreasing  area,  which  means  that 
the  current  density  increases  and  thus  diminishes  the 
number  of  univalent  ions  forming  in  a  given  time.  This 
hypothesis  accounts  for  the  fact  that  the  excess  of  the  loss 
in  weight  of  the  anode  over  the  increase  in  weight  of  the 
cathode  varies  inversely  as  the  time  during  which  electroly- 
sis is  continued.  Moreover,  it  explains  why  the  anode 
surface  becomes  rough  or  pitted,  as  chemical  solution 
alone  without  the  formation  of  this  protective  metallic 
powder  would  naturally  tend  to  keep  the  anode  surface 
smooth.  Smooth  surfaces  are  only  secured  when  cuprous 
ions  are  produced  in  negligible  quantities,  as  when  high- 
current  densities  are  maintained.  Additional  proof  of  the 
correctness  of  the  above  hypothesis  lies  in  the  absence  of 
any  such  anode  powder  in  the  electrolysis  of  chloride  solu- 
tions with  copper  anodes. 

The  separation  of  the  red  powder  of  metallic  copper  at 
the  anode  in  sulphate  solutions  furnishes  a  valuable  means 
of  detecting  the  purity  of  the  copper  that  is  being  dissolved;, 
for  even  very  small  amounts  of  impurities  produce  a  darken 
ing  in  color  of  the  separated  anode  powder  and  anode  itself, 
so  that  anodes  of  all  sorts  of  copper  not  previously  refined 
electrolytically,  or  of  copper  deposited  so  carelessly  as  not 
to  avoid  the  codeposition  of  such  impurities  as  arsenic  or 
antimony,  invariably  turn  very  dark.  Hence  one  may 
easily  determine  if  the  electrolytic  process  is  being  properly 
carried  on  by  periodically  removing  samples  of  the  cathode 
copper  and  suspending  them  as  anodes.  With  the  low- 
current  densities  in  vogue  at  the  Hamburg  Refinery  the 
anode  residue  naturally  carries  considerable  finely  divided 
metallic  copper.  The  latter  product  is  probably  the  chief 
cause  of  the  gradual  decrease  of  the  acidity  of  the  electro- 
lyte and  increase  of  its  copper  sulphate  contents,  as  it  readily 
dissolves  in  dilute  sulphuric  acid  in  contact  with  air  to 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  23 

copper  sulphate.  This  increase  of  the  bluestone  contents 
and  decrease  of  acidity  is  therefore  especially  noticeable 
in  installations  in  which  air  is  used  to  circulate  the  solution 
and  equalize  its  density,  and  is  not,  in  WohlwilTs  opinion, 
due  chiefly,  as  was  formerly  thought  probable,  to  the 
chemical  action  of  the  dilute  sulphuric  acid  on  the  cathode 
copper.  At  Hamburg  fully  2%  of  the  copper  contents  of 
the  anodes  are  recovered  annually  in  the  form  of  blue  stone. 

Another  regular  constituent  of  the  anode  slimes  of 
refineries  is  chlorine  combined  with  copper.  Whenever 
the  water  used  in  electrolysis  contains  large  quantities  of 
chlorides,  the  anodes  are  covered  with  a  white  coating  of 
cuprous  chloride,  which  darkens  in  time  through  the  action 
of  the  air  to  dirty  green-colored  oxychloride.  Eventually 
this  is  further  decomposed  by  the  sulphuric  acid  of  the 
electrolyte  and  contributes  also  to  the  increase  of  the  blue- 
stone  contents  of  the  latter.  Copper  electro-deposited  from 
chloride  solutions  and  salty  river-water  always  contains 
chlorine  when  low-current  densities  are  employed.  It  may 
then  be  noticed,  when  cathodes  are  arranged  as  end  plates, 
that  the  backs  of  the  latter  become  covered  with  white  or 
green  cuprous  chloride.  The  latter  sometimes  adheres  so 
firmly  as  to  occasion  considerable  trouble  in  the  refinery 
and  necessitate  the  partial  resolution  of  such  plates,  or  the 
substitution  of  an  anode  for  the  cathode  at  the  ends  of 
such  tanks,  to  distribute  the  current  density  uniformly 
over  the  cathodes,  and  thus  obtain  good  electrolytic  copper 
on  all  of  them. 

Wohlwill  found  that  the  copper  deposited  on  lead  strips,, 
hung  as  cathodes  alongside  of  the  regular  cathode  sheets, 
as  a  means  of  checking  the  changes  in  the  electrolytic  prod- 
uct, when  stripped  off  weekly  was  very  brittle  imme- 
diately after  starting  a  tank  system  with  an  electrolytic 
solution  containing  salty  water,  and  that  the  deposits  made 
later  were  less  and  less  brittle.  After  running  for  a  few 


24  MODERN  ELECTROLYTIC  COPPER  REFINING. 

weeks  the  deposited  copper  was  so  tough  that  it  could  be 
bent  back  and  forth  twenty'  times  without  breaking.  De- 
terminations then  made  proved,  according  to  Dr.  Wohlwill, 
that  the  brittleness  of  the  cathodes  varied  directly  as  the 
chlorine  contents  of  the  latter  and  of  the  solutions. 

In  my  opinion  this  statement  requires  modification, 
at  least  in  so  far  as  its  bearing  on  American  practice  and 
•conditions  is  concerned,  for  refiners  in  the  United  States 
find,  in  starting  deposition  from  a  normal  acidified  copper 
sulphate  solution  free  from  hydrochloric  acid,  that  the 
starting  sheets  are  generally  brittle,  and  that  good  tough 
starting  sheets  may  be  secured  by  adding  a  small  pitcher- 
ful  (about  300  cc.)  of  hydrochloric  acid  to  each  tank.  Dr. 
Wohlwill  also  came  to  the  conclusion  that  it  would  not  be 
good  practice  to  employ  an  electrolyte  free  from  chlorides. 
He  encountered  great  difficulty  for  many  years  at  the  Ham- 
burg Refinery,  because  periodically  the  deposited  copper 
became  covered  with  octahedral  crystal  aggregates.  Al- 
though these  crystal  groups,  often  as  much  as  10  cm.  long, 
consisted  of  pure  copper,  practical  considerations  demanded 
taking  means  for  preventing  their  formation  or  their  prompt 
removal,  naturally  at  the  cost  of  much  labor  and  expense, 
and  often  of  serious  delay  in  the  contract  time  of  deliver- 
ing cathodes.  It  was  found  that  these  troubles  reached 
their  maximum  when  the  water  used  as  the  basis  of  the 
•electrolyte  contained  the  least  salt,  say  in  January,  and 
were  least  when  the  solution  contained  the  most  salt,  as  in 
July  and  August.  The  addition  of  sodium  or  magnesium 
chloride  in  the  first  case  immediately  improved  matters. 
However,  it  did  not  entirely  prevent  the  formation  of  needle- 
like  projections,  so  that  a  satisfactory  explanation  of  the 
above  phenomenon  is  still  wanted.  The  peculiar  dis- 
covery was  made  later  that  a  solution  of  the  above  diffi- 
culty lay  simply  in  periodically  interrupting  the  process 
of  electrolysis.  By  stopping  the  action  of  the  current  in 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  25 

all  the  tanks  for,  say,  half  an  hour  during  each  day,  Wohl- 
will  found  that  the  sprouting  of  the  cathodes  was  dimin- 
ished to  such  an  extent  as  not  to  require  any  further 
special  attention,  and  has  now  adopted  this  practice  in 
the  Hamburg  Refinery. 

As  far  back  as  1886,  Huebl  determined  experimentally 
that  the  tensile  strength  and  hardness  of  electrolytic  copper 
is  not  dependent  on  the  concentration  of  the  electrolytic 
solution,  but  increased  with  increased  current  density,  and 
reached  maximum  values  with  an  electrolyte  containing 
20%  bluestone  when  the  current  density  was  22  to  30 
amperes  per  square  foot.  With  the  above  composition 
of  solution  the  highest  elastic  limit  was  obtained  when  the 
current  density  reached  10  to  15  amperes  per  square  foot 
and  the  greatest  toughness  at  6  amperes  per  square  foot. 

Foerster  and  Seidel  finally  investigated  the  influence  of 
temperature  during  the  electrolysis  of  copper,  and  in  1889 
published  figures  showing  that  they  secured  the  toughest, 
finest,  and  most  evenly  crystallized  copper  when  they 
heated  the  electrolyte  to  40°  C. 

Woolsey  McA.  Johnson*  assumes  that  ordinary  copper 
anodes  may  be  considered  as  being  mixtures  of  pure  copper 
and  copper-silver  alloys,  cuprous  oxide,  and  oxides  of  anti- 
mony and  arsenic,  or  solutions  of  these  alloys  and  oxides 
in  pure  copper,  and  states  that,  in  his  opinion,  because 
the  electrical  resistance  of  copper-silver  alloys  and  of  the 
oxides  is  higher  than  that  of  pure  copper,  the  silver  alloy 
and  oxides  would  tend  to  ''slime"  under  normal  condi- 
tions and  thus  tend  to  keep  the  solution  in  a  pure  con- 
dition. To  explain  these  views,  which  have  been  more  or 
less  well  recognized  since  1885,  when  Dr.  Kiliani's  pioneer 
investigations  were  published,  Johnson  has  recourse  to  the 
following  known  facts: 

*  Paper  read  at  the  meeting  of  the  American  Electrochemical  Society, 
Sept.  1 6,  1902. 


26  MODERN  ELECTROLYTIC  COPPER  REFINING. 

1.  Every  metal  has  a  certain  specific  electrolytic  ten- 
sion or  voltage  depending  upon  its  temperature,  physical 
condition,  and  the  solution  in  which  it  dips. 

2.  Every  metal  has  a  specific  electrical  conductivity. 

3.  These   two   properties  are   profoundly  modified  by 
alloying  with  other  metals. 

On  these  properties  of  the  resulting  alloys  segregated 
in  the  anode  depends  the  selective  electrochemical  dis- 
solution. 

Metals  unite  with  one  another  to  form  alloys,  in  most 
cases  with  the  evolution  of  heat,  and  the  atoms  are  then 
united  with  a  firmer  bond.  In  other  words,  the  free  energy 
is  diminished,  and  as  the  electrolytic  solution  tension  is 
measured  by  the  free  energy  of  the  metal,  in  normal  solu- 
tion of  its  ions,  it  also  must  decrease.  The  resultant 
product  is  harder  and  has  less  tendency  to  dissolve. 

That  most  alloys  of  any  two  metals  show  a  poorer  con- 
ductivity than  the  mean  conductivity  of  the  metals  com- 
posing such  alloy,  and  in  many  cases  than  the  conductivity 
of  either  metal  alone,  is  well  known.  These  facts  have  an 
important  bearing,  in  electrolytic  refining,  in  determining 
the  behavior  of  alloys  and  oxides  contained  in  ordinary 
copper  anodes.  For  instance,  if  we  consider  a  particle  of 
silver-copper  surrounded  by  pure  copper  crystals,  the 
effect  of  the  great  difference  in  electrical  conductivity  is 
pretty  certain  to  shunt  the  current  around  this  silver- 
copper  alloy  and  finally  dissolve  its  copper  backing.  It 
then  can  be  brushed  off  into  the  slime.  This,  of  course, 
applies  to  all  the  alloys  (and  oxides)  that  have  a  low  con- 
ductivity. 

Arsenic  and  antimony,  were  they  present  in  the  anode 
as  metals,  would  have  a  greater  tendency  to  dissolve  than 
copper,  because  of  their  high  electrolytic  solution  tension. 
Fortunately  for  the  electrolytic  refiner,  however,  the  larger 
portion  of  these  elements  are  thoroughly  oxidized,  either 


DEVELOPMENT,  METHODS,  AND  APPARATUS  27 

in  the  converter  or  reverberatory  furnace.  The  copper  is 
then  brought  to  * '  set "  in  the  refining  furnace  before  cast- 
ing into  anodes  if  the  copper  is  not  cast  into  anodes  direct 
from  the  converter,  receiver,  or  the  mixer.  The  heats  of 
oxidation  of  arsenic  or  antimony  being  many  times  larger 
than  that  of  copper,  the  oxides  of  the  former  metals  are  not 
reduced  to  any  extent  in  the  ''poling"  operation  in  the 
refining  furnace  as  long  as  any  cuprous  oxide  is  left.  Ar- 
senic and  antimony  are  thus  present  in  oxidized  anodes 
mainly  as  insulators,  and  as  such  pass  into  the  slimes 
directly. 

Treatment  of  Solutions  and  Making  Bluestone. — The  ten- 
dency of  the  electrolyte  with  long  use  in  circulation  to 
dissolve  or  carry  in  suspension  impurities  in  dangerous 
quantities,  so  that  its  continued  use  would  cause  disturb- 
ance or  the  deposition  of  arsenic,  antimony,  bismuth,  and 
other  metals  or  of  their  combinations  on  the  cathodes, 
i.e.,  the  production  of  a  copper  unfit  for  electrical  purposes, 
must  be  opposed  either  by  regularly  purifying  the  solution 
and  continuing  its  use,  or  better,  by  withdrawing  a  portion 
of  the  electrolyte  from  the  regular  circulation  system 
altogether,  treating  it  separately  and  replacing  the  por- 
tions so  withdrawn  by  an  equal  quantity  of  fresh  and  pure 
solution.  In  most  works  this  purification  or  withdrawal 
of  the  solution  does  not  occur  periodically,  but  is  carried 
out  as  one  continuous  operation,  a  certain  portion  of  the 
electrolyte  always  being  under  treatment.  Moreover,  as 
the  electrolyte  also  tends  to  become  richer  in  copper  sul- 
phate than  the  standard  fixed  upon,  this  excess  of  copper 
must  likewise  be  removed,  either  by  depositing  out  the 
excess  of  metal  in  special  tanks  with  lead  anodes  and  very 
strong  currents  or  recovering  the  copper  as  bluestone  by 
crystallization.  Both  methods  are  commonly  employed 
in  the  same  refinery. 

After  the  recovery  of  copper  vitriol  from  the  discarded 


28  MODERN  ELECTROLYTIC  COPPER  REFINING. 

electrolyte,  by  concentrating  the  solution  up  to  38°  to 
42°  B.  and  crystallizing  out  the  contained  blue  stone,  the 
crystals  formed,  if  necessary,  being  purified  by  repeated 
solution  and  crystallization  until  of  marketable  purity,  the 
impure  mother  liquors  are  treated  for  the  recovery  of  the 
remainder  of  the  copper,  usually  by  precipitation  with 
scrap  iron,  in  which  case  the  acid  is  usually  wasted,  or  by 
such  means  as  secure  the  sulphuric  acid  in  addition. 

The  sulphuric  acid  may  be  recovered  by  evaporating 
down  the  foul  solution  until  the  basic  salts  of  iron  and 
copper  separate  out  and  withdrawing  the  supernatant 
sulphuric  acid  for  use  in  treating  silver  slimes  or  in  acid- 
parting  of  dore  bars. 

It  is,  I  think,  a  rather  dangerous  practice  to  allow  the 
impurities  to  accumulate,  before  regenerating  the  electro- 
lyte, until  the  quality  of  the  copper  is  jeopardized,  as  noted 
in  one  plant.  A  regeneration  method  that  has  given  com- 
plete satisfaction  is  described  in  this  monograph  under 
the  caption  of  the  Kalakent  Works  in  Russia.  It  consists, 
briefly,  in  neutralizing  the  sulphuric  acid  in  the  solution 
by  passing  it  over  dead  roasted  matte  and  through  roasted 
copper  ores,  diluting  and  heating  the  solution  to  50°  C., 
and  injecting  compressed  air  through  it,  whereby  the  con- 
tained impurities  are  precipitated,  aided  by  suspending 
anode  scrap  in  the  solution  to  completely  neutralize  the 
same  and  form  copper  sulphate.  After  the  separation  of 
the  impurities  the  solution  is  concentrated  and  clarified 
in  special  tanks,  and  being  now  pure  enough,  is  acidified 
and  returned  to  the  copper-depositing  system  for  reuse 
as  normal  electrolyte.  The  excess  of  purified  electrolyte 
which  gradually  accumulates  with  this  regeneration  method 
is  worked  up  into  bluestone  as  usual. 

Several  similar  methods  of  purifying  the  electrolyte 
have  been  suggested,  such  as  (i)  filtration  through  a  bed 
of  copper  oxide,  and  (2)  oxidation  with  jets  of  air. 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  29 

The  method  of  purification  believed  to  be  in  use  at 
Anaconda  consists  in  repeatedly  passing  the  impure  elec- 
trolyte through  a  filter  of  oxidized  granulated  copper,  which 
precipitates  part  of  the  impurities,  and  in  oxidizing  the 
solution,  now  neutral  and  saturated  with  copper,  by  intro- 
ducing jets  of  air.  The  oxidation  is  said  to  cause  the 
partial  precipitation  of  the  iron  and  other  impurities  in  the 
solution. 

An  analogous  improvement  in  the  mode  of  circulating 
the  solution  was  introduced  into  the  old  Guggenheim  Re- 
finery. This  is  based  upon  the  well-known  action  of 
Pohle's  air-lift  or  of  Siemens'  ' '  geyser-pump. ' '  It  consists 
in  blowing  air  under  3  or  4  pounds  pressure  into  the  elec- 
trolyte by  means  of  lead  pipes  in  such  a  way  that  solution 
is  drawn  from  the  bottom  of  the  tank  by  a  lower  pipe  and 
delivered  into  an  upper  pipe,  to  be  discharged  back  into 
the  tank  through  a  large  number  of  perforations  in  this 
upper  pipe.  The  electrolyte  is  thereby  subjected  to  the 
oxidizing  influence  of  air-jets,  whereby  the  precipitation 
of  some  of  the  impurities  suspended  in  the  electrolyte  is 
facilitated  and  the  latter  is  clarified.  Many  refiners  believe 
that  a  large  portion  of  the  arsenic,  antimony,  silver,  etc., 
found  in  poor  cathode  copper  is  not  deposited  from  the  bath 
electrolytically,  but  mechanically,  by  suspended  impuri- 
ties settling  on  the  rough  surface  of  the  cathode.  This  is 
especially  the  case  when  high  densities  or  cloudy  solutions 
containing  floating  impurities  are  employed.  The  advan- 
tage of  a  rapid  clarification  of  the  electrolyte  is  therefore 
evident.  At  first  the  importance  of  the  air  circulation 
and  oxidation  system  was  much  exaggerated,  especially 
as  regards  the  removal  of  the  arsenic,  and  a  claim  was  made 
that  it  would  altogether  obviate  the  necessity  of  the  usual 
system  of  circulation  and  purification.  Although  such 
general  statements  were  not  justified,  the  fact  remains  that 
the  air  circulation,  if  assisted  during  two  or  three  hours 


3°  MODERN  ELECTROLYTIC  COPPER  REFINING. 

in  every  twelve  by  the  general  circulation  of  the  solution 
from  tank  to  tank,  gave  better  results  than  when  the  old 
system  was  used  alone. 

The  recovery  of  the  bluestone  from  the  discarded 
electrolyte  is  often  accomplished  as  follows : 

The  solution  is  first  boiled  in  lead-lined  tanks  with 
granulated  or  scrap  copper,  steam  and  air  being  introduced 
by  means  of  a  Koerting  injector,  so  as  to  neutralize  the 
free  acid  and  to  increase  the  copper  contents  of  the  solu- 
tion to  the  degree  desired.  It  is  then  pumped  up  to  the 
crystallizing  tanks,  in  which  bluestone  is  secured  by  allow- 
ing the  copper  sulphate  to  crystallize  out,  as  the  solution 
cools,  on  bands  of  lead  suspended  in  the  saturated  solution. 
The  mother  liquor  siphoned  off  contains  most  of  the  arsenic 
and  antimony  originally  present  in  the  electrolyte,  together 
with  some  remaining  copper.  To  recover  the  latter,  the 
mother  liquor  is  usually  treated  in  special  tanks  with  sheets 
of  scrap  iron.  This  metal  first  precipitates  out  the  copper 
and  then  the  arsenic,  so  that  a  black  precipitate  is  finally 
secured,  containing  at  times  as  much  as  60%  of  metallic 
arsenic.  The  impure  precipitate,  finally,  is  melted  and 
reduced  down  into  arsenical  copper  bars,  or  occasionally 
utilized  in  the  manufacture  of  compounds  of  arsenic  and 
copper,  such  as  Paris  green. 

At  the  Baltimore  Copper  Works  the  adopted  method 
of  preserving  the  purity  of  the  main  electrolyte  consists  in 
periodically  withdrawing  a  fixed  portion — say  one-fifth— 
of  the  electrolytic  solution  for  manufacture  into  blue 
vitriol  and  replacing  it  by  fresh  electrolyte,  so  as  to  keep 
the  percentage  of  impurities  in  the  circulating  electrolyte 
down  to  an  approximately  constant  figure.  The  composi- 
tion of  the  solution,  strength  of  current,  and  other  factors 
of  refining  not  being  permitted  to  vary  within  large  limits, 
it  is  comparatively  easy  to  produce  a  nearly  uniform  quality 
of  copper.  The  bluestone  recovered  is  sold  at  a  fair  profit, 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  31 

and  the  mother  liquor  from  the  blue  vitriol  works  is  finally 
treated  with  scrap  iron  to  precipitate  the  last  2%  or  3% 
of  copper  it  contains. 

A  mode  of  treatment  similar  to  the  Baltimore  process 
is  employed  at  the  Balbach  Refinery.  Here  the  standard 
composition  of  the  electrolyte  is  kept  up  by  periodically 
running  off  a  portion  and  replacing  it  with  pure  solution. 
The  impure  liquid  is  then  pumped  to  the  vitriol  works,  in 
which  sulphates  of  copper,  iron,  and  nickel  are  recovered 
from  the  solution  by  a  process  of  fractional  crystallization, 
.after  which  the  mother  liquor  is  boiled  down  to  recover 
arsenious  and  sulphuric  acid.  If  the  electrolyte  contains 
considerable  antimony,  part  of  it  is  said  to  precipitate  as 
gray  metallic  antimony  or  as  antimonious  acid  in  the  dis- 
charge launders. 

From  a  consideration  of  all  of  the  above-described 
methods,  we  reach  the  conclusion  that  a  crystallizing  plant 
for  the  recovery  of  blue  vitriol,  although  bulky  and  cum- 
bersome, is  still  considered  a  necessary  adjunct  to  copper 
refineries.  However,  by  diminishing  the  need  of  blue 
vitriol  works  of  large  capacity,  and  thus  avoiding  the 
•excessive  production  of  what  is  often  a  drug  on  the  market, 
the  adoption  of  the  best  methods  described  above  by  refin- 
ing companies  has  certainly  resulted  in  keeping  down  the 
cost  of  refining  copper. 

Ottokar  Hofmann  describes  his  important  improve- 
ments in  the  method  and  apparatus  for  purifying  foul  solu- 
tions and  making  bluestone  substantially  as  follows  in  The 
Mineral  Industry,  vol.  x.  As  applied  to  foul  refinery  solu- 
tions, Hofmann' s  process  begins  in  elevating  the  latter  by 
means  of  a  pressure  tank,  shown  in  Figs.  9,  10,  and  n, 
to  the  purifying  towers,  the  hard-lead  pumps  formerly 
used  for  handling  copper  solution  having  proved  failures. 
On  account  of  occasionally  having  to  handle  residues,  the 
pressure  tanks  are  in  an  upright  position  and  are  constructed 


32  MODERN  ELECTROLYTIC  COPPER  REFINING. 

as  follows :  * '  The  body  consists  of  two  cylindrical  sections 
4  ft.  long  and  4  ft.  6  in.  in  diameter,  the  bottom  being  of  a 
spherical  section  of  2  ft.  3  in.  radius  and  the  top  rounding 
upward  to  a  height  of  6  in.  above  the  rim.  The  sections 


FIG.  9. — Plan  showing  Size  of  Openings. 


FIG.  10. — Section  on  Line  AB.  FIG.   n. — Plan  of  Supporting  Frame. 

FIGS.  9,  10,  and  n. — Cast-iron  Pressure  Tank. 

are  tightly  flanged,  with  a  rubber  gasket  between.  Four 
pipe  connections  are  made  through  the  top;  the  discharge 
pipe  entering  through  the  center  passes  nearly  to  the  bot- 
tom and  the  filling  pipe,  air-inlet  and  air-outlet  pipes  are 
conveniently  arranged  around  it.  By  proper  connection 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  33 

with  the  filling  pipe  and  by  the  use  of  valves,  one  pressure 
tank  is  made  to  serve  four  receiving  tanks.  The  upper 
cylindrical  section  is  provided  with  a  manhole,  and  the 
tanks  are  lined  first  with  lead  and  then  with  wood  to  pro- 
tect the  lead  from  wear  by  abrasion.  The  air  pressure 
required  is  from  40  to  50  Ib.  Fig.  9  shows  a  top  view,  and 
Fig.  10  a  vertical  cross-section  of  an  upright  pressure  tank, 
while  Fig.  n  illustrates  the  supporting  frame.  This  tank 
is  somewhat  smaller  than  those  used  in  the  Argentine  blue 
vitriol  plants  and  has  one  cylindrical  section  instead  of 
two.  The  general  arrangement,  however,  is  the  same. 
The  air  inlet  extends  downward  along  the  side,  ending  near 
the  discharge  pipe,  in  order  to  keep  any  residues  near  the 
outlet  in  a  loose  condition  and  prevent  the  pipes  from 
clogging.  For  this  reason  it  is  advisable  to  have  a  small 
stream  of  air  enter  during  filling.  The  residues  are  rather 
heavy  and  occasionally  pack  tightly  around  the  discharge 
pipe  in  quite  a  thick  layer,  which,  on  applying  the  pressure, 
would  be  forced  in  this  compact  condition  into  the  dis- 
charge pipe  and  the  pipe  leading  to  the  purifying  towers, 
causing  them  to  become  clogged. 

;<The  purifying  or  refining  towers,  as  shown  in  the 
attached  dimensioned  sketch,  are  made  of  California  red- 
wood, which  makes  an  excellent  material  to  resist  the  action 
of  hot  cupric  sulphate  solution.  They  are  9  ft.  in  diameter 
at  the  bottom  and  constructed  of  staves  16  ft.  long  and 
4  in.  thick,  which  are  well  hooped  with  round  iron;  the 
bottom  and  top  are  flat.  The  towers  are  firmly  fastened 
to  a  strong  wooden  trestle,  which  in  turn  is  anchored  to  a 
concrete  foundation.  This  construction  is  called  for  to 
guard  against  the  oscillating  movement  of  the  tanks  from 
the  action  of  the  contained  solution,  which  is  set  in  violent 
motion  by  the  ascending  air.  Inside  the  tower,  about  19 
in.  above  the  bottom,  the  4-in.  lead  air  pipe  enters  and  is 
connected  with  a  perforated  6-in.  lead  pipe  which  extends 


34  MODERN  ELECTROLYTIC  COPPER  REFINING. 

diametrically  to  the  opposite  side  and  is  closed  at  the 
farther  end.  Outside  of  the  tower  the  air  pipe  extends 
upward  to  above  the  top  of  the  tower,  and  thence  down- 
ward to  the  discharge  pipe  of  an  air  compressor.  This 
arrangement  is  necessary  in  order  to  prevent  the  solution 
from  flowing  to  the  air  pump.  At  the  same  level  with  the 
air  inlet,  the  4-in.  discharge  pipe  enters,  which  is  provided 
with  a  hard-lead  valve  placed  close  to  the  outside  of  the 
tower.  At  about  the  same  level  a  i-in.  steam  pipe  enters 
for  heating  the  charge.  The  lead  steam  coil  formerly  used 
has  been  discarded  and  the  heating  is  now  accomplished 
by  direct  steam.  This  change  was  necessary  as  the  lead 
coil  required  frequent  repairs,  and,  moreover,  the  heating 
effect  of  direct  steam  is  much  greater  than  that  of  a  steam- 
heated  coil.  The  solution  does  not  lose  in  strength  through 
the  condensation  of  the  steam,  the  evaporation,  which  is 
favored  by  the  'ascending  air,  fully  equalizing  the  dilution. 
The  top  of  the  tower  is  provided  with  an  8-in.  pipe  for  the 
escape  of  the  vapor  and  air,  and  with  a  4-in.  pipe  for  charg- 
ing the  crude  solution.  An  opening  in  the  center  sup- 
ports a  small  hopper  which  is  filled  with  roasted  matte, 
and  by  lifting  a  cone  valve  the  charging  is  kept  under  good 
control.  By  the  action  of  the  air  and  the  cupric  oxide  of 
the  roasted  copper  matte  in  the  neutral  solution,  the  im- 
purities are  oxidized  and  precipitated.  The  perforated 
cones,  of  which  there  were  three  in  each  tower  for  the  dis- 
tribution of  the  compressed  air  throughout  the  solution, 
have  been  replaced  by  a  sufficiently  large  perforated  pipe. 
This  change  simplifies  the  construction  without  impairing 
the  efficiency  of  the  tower.  In  charging  the  towers,  room 
must  be  left  for  the  increase  in  volume  of  the  solution  which 
occurs  as  soon  as  the  air  is  supplied.  A  tower  of  the  new 
type  can  be  charged  with  about  5000  gal.  of  solution,  and 
as  three  such  charges  can  be  refined  in  24  hours  the  working 
capacity  of  one  tower  is  1 5,000  gal.  per  day.  Eight  of  these 


4  Valvepn  here,.         4*  ValVb  HCT«. 


'Cast  Iron  Flange* 
^RuMHsr  Gasket 


FIG.  12. — Hofmann's  Tower  for  Refining  Cupric  Sulphate  Solutions. 


36  MODERN  ELECTROLYTIC  COPPER  REFINING. 

towers  are  in  use  at  the  Argentine  plant.  Fig.  12  shows  a. 
vertical  section  of  a  tower  of  the  latest  construction.  The 
air-inlet  pipe,  which  is  horizontal  within  the  tank,  has  only 
its  lower  half  perforated  to  prevent  the  inflow  of  matte  and 
precipitate.  The  steam  pipe  was  formerly  inserted  direct 
through  the  wood,  but  as  the  latter  became  affected  by  the 
heat,  it  now  enters  through  the  manhole  cover.  A  similar 
effect  was  noticed  with  the  bolts  which  passed  through  the 
wood  to  hold  the  flanges  of  the  manhole,  air  inlet,  and  dis- 
charge pipe.  In  the  new  construction  these  holes  in  the 
staves  are  cut  much  larger,  and  neither  the  frame  nor  the 
bolts  are  in  contact  with  the  wood.  This  is  shown  in  the 
illustration.  The  two  pipes  are  arranged  in  a  similar 
manner.  All  iron  parts  on  the  inside  of  the  tower  are 
covered  with  heavy  sheet  lead. 

' '  When  the  reaction  is  completed  and  the  solution  freed' 
from  impurities,  the  charge  is  drawn  off  and  forced  through 
a  filter  press.  The  tower  residues,  consisting  mainly  of 
precipitated  iron,  arsenic,  antimony,  and  some  un decom- 
posed matte,  contain  also  some  basic  copper  sulphate.  To 
remove  the  last-named  substance  the  residues  are  treated 
in  a  stir  tank  with  a  2.5%  to  3%  cold  acid  solution,  which 
dissolves  the  basic  copper  salt,  leaving  the  impurities  un- 
affected with  the  exception  of  iron,  which  is  acted  on  very 
slightly.  The  refined  solution  is  conveyed  to  settling  tanks 
from  which  the  evaporating  tanks  are  supplied. 

''The  evaporating  department  furnishes  the  crystal- 
lizing department  with  about  90,000  gal.  of  concentrated' 
solution  daily.  To  supply  this  amount  an  improvement 
over  the  old  pan  evaporators  with  under-fire  or  steam  coils, 
was  requisite,  and  as  vacuum  evaporators  could  not  be 
adopted,  I  have  introduced  an  economical  and  effective 
evaporator  at  Argentine,  which  is  illustrated  in  Figs.  13 
and  14.  The  principles  observed  in  the  construction  of 
this  evaporator  are  the  application  of  the  hot  furnace  gases 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  37 

-direct  to  the  heating  of  the  solution  and  the  almost  com- 
plete utilization  of  the  heat  contained  in  them.  The 
-apparatus  consists  of  a  flat  wooden  tank  with  the  excep- 
tion of  a  2 -ft.  space  at  the  front  end,  which  is  made  of 
steel,  so  that  the  wood  will  not  be  in  too  close  proximity 
to  the  furnace.  The  tank  is  65  ft.  long,  12  ft.  wide,  and 
2  ft.  deep,  and  is  lead-lined,  the  two  ends  having  much 
heavier  lead  lining  than  the  sides  and  bottom.  It  is  trav- 
ersed longitudinally  by  13  six-inch  lead  pipes  and  rests 
on  a  wooden  trestle-work  of  a  proper  height  to  correspond 
with  the  height  of  the  furnace.  At  the  furnace  end  in  each 
lead  pipe  is  inserted  a  5-in.  iron  pipe  4  ft.  long  provided 
-at  the  outer  end  with  a  flange.  The  iron  pipes  serve  to 
protect  the  lead  pipes  from  immediate  direct  contact  with 
the  red-hot  gases  from  the  furnace;  they  also  make  the 
connections  between  the  lead  pipes  of  the  tank  and  the 
iron  pipes  of  the  furnace. 

1 '  The  furnace  is  comprised  of  the  fire-place  C,  the  dust- 
chamber  D,  and  the  heat-distributing  chamber  D' .  At 
a  proper  height  in  the  wall  of  the  distributing  chamber 
nearest  the  tank  are  13  openings,  in  each  of  which  is  in- 
serted a  short  cast-iron  pipe  5  in.  in  diameter,  with  a  flange 
at  the  outer  end.  Each  pipe  is  connected  with  its  corre- 
sponding lead  pipe  in  the  tank  by  a  cast-iron  S-shaped 
elbow  y,  which  allows  the  introduction  of  the  compressed- 
air  pipe  E  for  removing  any  accumulation  of  ashes  in  the 
lead  pipes  of  the  tank. 

' '  An  American  .underfed  stoker  is  used  for  the  slack- 
coal  fuel,  and  affords  practically  perfect  combustion,  which 
is  of  great  importance,  as  otherwise  the  lead  pipes  would 
soon  become  coated  with  soot  and  lose  much  of  their  effi- 
ciency to  transmit  the  heat  to  the  solution. 

' '  The  opposite  end  of  the'  lead  pipes  in  the  tank  are 
•connected  with  the  brick  suction-chamber  0,  which  in  turn 
is  connected  by  a  galvanized  iron  pipe  R  with  a  suction 


38  MODERN  ELECTROLYTIC  COPPER  REFINING. 

fan  P,  the  gases  being  discharged  into  the  underground 
flue  5.  This  flue  serves  in  common  to  collect  the  waste 
gases  from  n  evaporators,  and  terminates  outside  the 
building  into  a  brick  chimney  40  ft.  in  height. 


FIG.  13.— Pan  Evaporator, 


FIG.  14. — Pan  Evaporator, 

;  *  The  top  of  the  pan  is  closed  with  a  wooden  cover  and 
joists  C  are  placed  across  the  pan  about. 5  ft.  apart,  having 
cleats  fastened  to  the  lower  side,  as  shown  in  Fig.  13.  The 
spaces  between  the  joists  are  covered  with  boards  resting 
on  the  cleats  and  pushed  close  together,  but  not  nailed, 
so  that  the  whole  or  part  of  the  cover  can  be  easily  removed. 
About  14  ft.  from  the  front  end  of  the  tank  is  a  i4-in.  suc- 
tion pipe  L,  connected  with  the  main  suction  pipe  M,  which 
crosses  all  of  the  evaporators  to  remove  the  water  vapors. 


DEVELOPMENT,  METHODS,  AND  APPARATUS. 


39 


This  main  suction  pipe  is  constructed  of  wooden  staves 
kept  tight  by  hoops.  The  suction  pipe  L  was  first  made 
of  lead,  but  by  some  unexplained  chemical  reaction  it  was 
destroyed  after  a  few  months  of  operation.  Later  a  wooden 


I 


u»  . 

_j                     fl_ 

tr 
I 

p       F        ft_ 

fj   nr 

Hr 

^ 

/ 

U"1-~       K 

_H  £^L 

A: 

// 

j?    y/ 

^^fci 

Longitudinal  Vertical  Section. 


Horizontal  Section. 


tube  was  substituted,  which  was  made  in  the  same  manner 
as  the  main  tube.  The  latter  is  in  connection  with  a  large 
fan  having  the  housing  and  wings  of  sheet  copper  and  the 
shaft  and  arms  of  brass.  This  fan  rapidly  removes  the 
vapor  from  each  evaporating  tank  and  by  its  use  the  build- 
ing, even  in  cold  winter  weather,  is  entirely  free  from  steam. 
A  wooden  stack  serves  for  the  discharge  of  the  fan,  and  the 
strength  of  the  exhaust  is  regulated  by  a  wooden  slide  N 
inserted  below  the  suction  pipe  L. 


40  MODERN  ELECTROLYTIC  COPPER  REFINING. 

' '  Close  to  the  end  of  the  evaporating  tank,  and  resting 
on  the  cover,  is  the  lead-lined  feed  box  V,  from  the  bottom 
of  which  is  a  short  pipe  or  nipple  leading  into  the  tank. 
The  solution  supply  pipe  T,  which  crosses  all  the  evapora- 
tors, is  connected  with  the  large  supply  tanks  and  serves 
to  convey  the  solution  to  each  evaporator  by  downtakes  U. 
The  outlet  of  the  evaporating  tank  is  in  the  side  near  the 
furnace  end  about  4  in.  above  the  hot-air  pipe  B  (Fig.  13). 

"The  operation  is  conducted  in  the  following  manner: 
The  pan  is  first  filled  to  the  level  of  the  outlet  with  the 
copper  sulphate  solution  to  be  concentrated,  the  fire  is 
then  started  and  the  suction  and  stoker  fans  set  in  motion. 
The  big  copper  fan  is  not  started  until  the  solution  becomes 
hot  enough  to  generate  steam.  During  the  operation  the 
level  of  the  solution  is  kept  at  the  same  height  by  the  occa- 
sional addition  of  new  solution  through  the  feed  box  V. 
When  it  is  found  by  test  with  a  Baume's  scale  that  the 
solution  near  the  outlet  has  attained  the  desired  concen- 
tration, a  continuous  stream  of  weak  solution  is  allowed 
to  flow  into  the  tank  from  the  feed  box,  which  starts  a 
continuous  outflow  of  concentrated  solution  through  the 
outlet.  The  amount  of  incoming  solution  is  regulated 
by  frequent  hydrometer  tests  of  the  solution  at  the 
outlet.  The  supply  of  fuel  by  the  automatic  stoker  being 
very  regular,  the  heat  of  the  evaporator  is  very  uniform, 
and  once  having  adjusted  the  proper  influx  of  the  weak 
solution  the  outflowing  stream  will  be  found  of  quite  con- 
stant concentration. 

"The  object  in  making  the  evaporating  pan  of  this 
length  is  to  utilize  the  heat  of  the  fire -gases  as  much  as 
possible.  The  glowing  hot  gases  entering  the  tubes  give 
off  the  main  part  of  their  heat  to  the  solution  within  a 
comparatively  short  distance  from  the  point  of  entrance 
and  cause  this  portion  of  the  solution  to  boil.  In  the  pas- 
sage of  the  gases  through  the  tubes  they  gradually  come 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  41 

into  cooler  regions  and^are  offered  an  excellent  opportunity 
to  give  off  more  of  their  heat  to  the  surrounding  solution, 
so  that  when  they  finally  leave  the  tubes  their  tempera- 
ture is  much  below  the  boiling  point  of  the  solution.  If 
the  tank  had  been  constructed  of  still  greater  length,  say 
100  or  125  ft.,  the  gases  would  have  left  the  tubes  at  a  tem- 
perature about  that  of  the  surrounding  air,  thus  completely 
utilizing  the  heat  generated.  With  the  6 5 -ft.  tank,  the 
pipes  at  the  exhaust  end  of  the  tank  can  be  touched  with 
the  hand. 

' '  The  greater  economy  and  efficiency  of  this  type  of 
evaporator,  as  compared  with  one  having  a  steam  coil  or 
bottom  fire,  is  apparent.  The  production  of  steam  in- 
volves a  considerable  waste  of  heat,  and  in  using  it  to 
evaporate  liquids,  its  circulation  through  coils  produces  a 
large  amount  of  condensed  water  at  a  temperature  very 
nearly  100°  C.,  the  heat  of  which  is  generally  lost.  To 
evaporate  by  direct  fire  under  the  bottom  of  a  pan  is  very 
inefficient  and  wasteful,  and  in  the  present  case,  in  which 
no  other  metal  but  lead  can  be  used  for  the  pan,  it  requires 
great  care  and  watchfulness  to  avoid  melting  the  metal. 

"For  concentrating  chemical  solutions  which  are  not 
affected  by  iron,  as,  for  instance,  copper  sulphate,  the  new 
evaporator  described  in  detail  above  can  be  constructed 
entirely  of  iron  or  steel  and  at  much  less  cost.  The  pan 
itself,  however,  should  always  be  placed  in  a  wooden  tank 
to  prevent  loss  of  heat  by  radiation. 

"The  outflowing  concentrated  solution  passes  into  a 
6-in.  lead  pipe  and  is  conveyed  to  a  collecting  tank,  which 
is  covered  to  prevent  the  cooling  of  the  liquor.  At  Argen- 
tine, one  pipe  serves  to  collect  and  convey  the  concentrated 
solution  from  n  evaporators.  From  the  solution  tank 
the  hot  solution  is  drawn  into  a  horizontal  pressure  tank, 
and  is  elevated  by  compressed  air  to  a  system  of  troughs 
placed  above  the  crystallizing  tanks.  The  troughs  are 


42  MODERN  ELECTROLYTIC  COPPER  REFINING. 

tightly  covered  with  planks  to  avoid  cooling,  which  would 
cause  crystals  to  form  in  them.  In  construction  the 
troughs  are  of  California  redwood,  10X11  in.,  in  sections 
of  1 6  ft.  The  ends  of  the  sections  butt  together  and  have 
an  intervening  rubber  gasket.  The  sections  are  drawn 
together  by  iron  flanges  fastened  to  the  sides  of  the  trough 
a  few  inches  from  the  end,  iron  bolts  passing  through  both 
flanges.  Brass  screws  are  used  in  making  the  troughs,  as 
iron  nails  or  screws  would  not  last.  The  joints  between 
the  bottom  and  the  sides  are  coated  with  a  fairly  thick 
cement,  which  is  made  by  boiling  together  waste  rubber, 
resin,  linseed  oil,  and  ferric  oxide.  The  cement  when 
properly  made  should  be  quite  liquid  when  very  hot-  and 
stiff  when  cold,  but  never  brittle  or  so  hard  that  it  cannot 
be  kneaded  between  the  fingers;  nor  should  a  piece  of  the 
stiff  cement  become  liquid  in  water  at  a  temperature  of 
80°  to  90°  C.  The  cement  is  elastic,  and,  as  it  never  har- 
dens, it  keeps  the  joints  well  filled  and  overcomes  the  diffi- 
culty which  arises  from  the  shrinkage  of  one  board  from 
another.  It  has  given  very  satisfactory  results  in  the 
Argentine  plant,  and  there  has  been  absolutely  no  leakage 
in  the  troughs,  which  in  aggregate  length  amount  to  nearly 
half  a  mile. 

"The  crystallizing  department  has  112  tanks,  each  of 
720  cu.  ft.  capacity  arranged  in  long  rows  intersected  by 
several  cross  passages.  Between  each  two  rows  is  a  track 
for  transporting  the  blue  vitriol  crystals,  on  either  side  of 
which  is  a  cement  channel  to  receive  and  convey  the  mother 
liquor.  The  lead-lined  wooden  crystallizing  tanks  did  not 
prove  satisfactory,  as  the  change  in  temperature  caused 
by  each  filling  with  hot  concentrated  solution  expanded 
the  lead  which  did  not  subsequently  contract  in  cooling; 
as  a  result  in  course  of  time  the  tank  lining  became  wrinkled 
and  broken  and  caused  leakage  and  expensive  repairs, 
The  entire  floor  of  the  blue  vitriol  plant  is  made  of  cement 


UtrULUPMENTt  METHODS,  AND  APPARATUS.  43 

in  order  to  collect  any  leakage  that  may  take  place.  At 
present  the  tanks  are  made  of  concrete,  and,  though  far 
superior  to  the  original  lead-lined  wooden  tanks,  they  do 
not  come  up  to  expectation  because  they  also  are  affected 
by  the  sudden  change  in  temperature  when  filled  with  the 
large  bulk  of  hot  concentrated  solution.  Although  con- 
structed with  walls  20  in.  thick,  small  cracks  result,  but 
leakage  can  be  prevented  by  plastering  a  little  cement  on 
the  outside  of  the  tank.  An  experimental  tank  which  has 
now  been  in  use  for  several  months  seems  to  answer  all  re- 
quirements. It  is  built  of  bricks,  having  in  the  center  of 
the  walls  a  2 -in.  space  filled  with  a  mixture  of  asphaltum 
and  sand,  which  extends  also  from  the  sides  under  the 
bottom  of  the  tank,  thus  practically  forming  a  tank  by 
itself  imbedded  in  the  brickwork.  When  heated  by  the 
sudden  filling  of  the  tank  with  hot  solution,  the  asphaltum 
softens,  and  when  gradually  cooled  it  contracts  without 
cracking. 

' '  On  the  top  of  each  tank  are  movable  wooden  frames 
supporting  numerous  strips  of  lead,  on  which  the  crystals 
form,  as  well  as  on  the  sides  and  on  the  bottom  of  the  tank. 
The  solution  remains  seven  days  in  the  tank.  At  the  ex- 
piration of  this  time  the  mother  liquor  is  drawn  off  and 
the  crystals  removed.  Ordinarily  16  tanks  are  discharged 
daily,  but  during  the  hot  summer  months  more  time  has 
to  be  given  for  the  crystallization,  and  fewer  tanks  are 
discharged  and  refilled  daily. 

'  The  mother  liquor  is  drawn  off  through  a  brass  tube 
close  to  the  bottom  of  the  tank  and  flows  in  the  above-men- 
tioned cement  channels  in  front  of  each  row  of  tanks  direct 
to  the  three  pressure  tanks  placed  in  a  pit.  These  tanks 
elevate  the  mother  liquor  to  large  storage  tanks,  where  it 
is  mixed  with  fresh  copper  sulphate  solution  from  the  dis- 
solving and  refining  departments,  and  is  ready  to  supply 
the  evaporators.  When  the  crystallizing  tank  is  empty, 


44  MODERN  ELECTROLYTIC  COPPER  REFINING.  , 

the  movable  frames  with  the  lead  strips  and  adhering 
crystals  are  lifted  by  a  block  and  chain  and  the  crystals 
knocked  off  with  a  wooden  paddle.  The  crust  of  crystals 
from  the  sides  is  broken  down.  Rails  are  laid  in  recesses 
near  the  rim  of  the  tanks  so  that  the  rails  of  the  two  oppo- 
site rows  of  tanks  form  a  track  for  a  hopper  mounted  on 
wheels.  The  crystals  are  shoveled  with  copper  shovels 
into  this  hopper,  which  fills  the  push-car  underneath  through 
a  spout  with  slide  in  the  center.  As  the  tanks  are  6  ft. 
deep,  the  crystals  have  to  be  thrown  at  least  7  ft.  high,  and 
in  doing  this  work  some  of  the  crystals  unavoidably  fall 
back  into  the  tank,  frequently  striking  the  shoveler.  It 
was  found  that  this  was  very  injurious  to  the  men,  espe- 
cially in  summer,  when  they  are  dressed  scantily  and  per- 
spire freely.  Their  bodies  became  covered  with  deep  sores, 
which  were  very  painful,  although  not  dangerous,  and  the 
men  naturally  shunned  the  work  and  had  to  be  replaced. 
Finally  this  branch  of  the  plant  was  closed  during  the 
months  of  July  and  August. 

' '  To  overcome  this  very  disturbing  feature,  I  have  con- 
structed and  set  in  successful  operation  the  device  illus- 
trated in  Fig.  15.  On  top  of  the  hopper  is  mounted  the 
frame  KK-wiih  a  turntable  and  circular  track  underneath 
which  rests  on  a  number  of  stationary  wheels  and  is  kept 
in  place  by  the  pin  P.  The  object  of  this  turntable  is  to 
make  the  apparatus  available  for  opposite  rows  of  tanks 
by  rotation  through  180°.  The  frame  K  is  provided  with 
a  belt  elevator  E  with  copper  cups,  which  can  be  brought 
into  a  horizontal  position  by  means  of  the  shaft  F.  On  the 
same  shaft  are  the  pullies  L  and  M  which  drive  the  elevator 
pulley  N.  The  lower  end  of  the  elevator  is  provided  with 
the  boot  B,  which  can  be  brought  down  to  within  a  short 
distance  from  the  bottom  of  the  tank  and  into  which  the 
-crystals  are  shoveled.  The  power  is  imparted  by  an  electric 
motor  on  the  platform  of  the  frame,  which  receives  the 


DEVELOPMENT,  METHODS,  AND  APPARATUS. 


45 


electric  current  by  an  overhead  wire  with  trolley  extending 
along  the  rows  of  tanks.  From  the  time  this  device  was 
introduced  the  men  were  protected  from  the  injurious  effect 


of  the  blue  vitriol  crystals  even  during  the  hot  summer 
months,  as  they  had  to  shovel  them  only  a  short  distance 
above  the  floor. 

"The  push-cars  containing  the  crystals  are  wheeled  to 


46  MODERN  ELECTROLYTIC  COPPER  REFINING. 

the  sizing  and  drying  department  and  lifted  by  a  platform' 
elevator  to  the  rim  of  a  bin,  into  which  the  crystals  are- 
dumped.  From  this  bin  the  crystals  are  fed  between  a 
fast-revolving  roll  and  a  plate  provided  with  teeth,  which, 
breaks  the  crusts  of  crystals  without  injuring  the  individual 
crystals.  After  passing  the  rolls  the  crystals  drop  into  a 
small  hopper  having  a  short  worm  conveyor  of  copper  at 
the  bottom,  which  feeds  a  belt  elevator  provided  with 
copper  cups.  The  elevated  crystals  drop  into  an  inclined 
trough  and  are  washed  by  a  stream  of  mother  liquor.  They 
then  drop  into  a  hexagonal  revolving  screen  having  the 
shaft  and  arms  of  brass.  The  screen  itself  is  of  maple  wood 
perforated  with  holes  0.375  m-  in  diameter.  All  crystals- 
smaller  than  0.375  in.,  together  with  the  mother  liquor,  pass 
through  a  second  inclined  trough  to  another  revolving 
screen,  which  is  of  sheet  copper  having  o.i25-in.  perfora- 
tions. The  mother  liquor,  with  the  very  fine  crystals, 
dirt,  and  sediment,  after  leaving  the  second  screen  is  con- 
veyed to  an  agitating  tank  and  heated  by  a  steam  jet  to 
dissolve  the  very  fine  crystals.  The  resultant  solution  is 
finally  sent  through  a  filter  press,  the  clear  liquor  flowing 
to  the  storage  tanks. 

"By  using  mother  liquor  to  wash  and  screen  the  crys- 
tals, the  fine  crystals  are  as  clean  and  pure  as  those  of 
larger  size.  At  the  present  time  the  blue  vitriol  crystals 
are  dried  in  10  brass  centrifugal  machines  and  conveyed 
to  the  storage  bins. 

1 '  The  crystals,  having  been  obtained  from  a  neutral 
solution,  are  of  a  very  deep-blue  permanent  color  which  is 
not  affected  by  light  except  in  the  direct  rays  of  the  sun. 
They  do  not  change  into  a  bluish-white  powder,  which  is 
the  case  with  crystals  made  from  an  acid  solution. ' ' 

The  American  Smelting  and  Refining  Co.  is  introducing 
the  essential  features  of  this  method  for  the  purification 
of  foul  electrolytic  solutions  at  its  Perth  Amboy  plant. 


DEVELOPMENT,  METHODS,  AND  APPARATUS.  47 

As  the  process  requires  the  electrolyte  to  be  first  neu- 
tralized, and  as  this  is  done  by  adding  to  it  cupric  oxide 
(roasted  copper  matte),  the  bulk  of  solution  obtained  will 
increase.  This  increase  may  be  worked  off  in  two  ways: 
i,  by  treating  the  surplus  solution  in  a  separate  system  of 
tanks  in  which  lead  anodes  and  cathodes  are  used,  copper 
being  removed,  while  sulphuric  acid  is  set  free  and  is  used  to 
acidify  that  part  of  the  refined  and  neutral  electrolyte  which 
goes  back  to  the  refinery;  or,  2,  by  making  blue  vitriol,  in 
which  case,  of  course,  sulphuric  acid  must  be  bought  for 
addition  to  the  refined  neutral  electrolyte.  Special  con- 
ditions in  any  given  case  determine  which  of  these  two 
methods  should  be  preferred. 

Treatment  of  Slimes. 
(By  ROBERT  L.  WHITEHEAD.) 

The  slimes  produced  in  the  electrolytic  refining  of  cop- 
per vary  in  precious  metal  content  from  1500  to  22,000  oz. 
silver  and  from  4  to  200  oz.  gold  per  ton,  the  copper  con- 
tained being  from  10%  to  40%,  in  the  form  of  metal, 
copper  oxide,  copper  sulphide,  and  copper  sulphate,  the 
last-named  combination  being  due  to  imperfect  washing 
of  the  slimes. 

The  usual  treatment  of  slimes  in  large  smelting  and 
refining  works  equipped  with  a  desilverizing  department 
is  to  add  the  dried  slimes  in  paper  bags  of  10  or  15  Ib. 
capacity  to  the  charge  of  retort  metal  on  the  cupel  hearth. 
The  copper  and  impurities  are  oxidized  and  pass  off  in  the 
slag,  while  the  gold  and  silver  is  absorbed  in  the  refined 
retort  metal  remaining  on  the  cupel.  The  copper  dross 
is  treated  in  a  shaft  furnace  for  the  recovery  of  the  copper, 
antimony,  and  lead,  the  copper  being  regained  as  copper 
matte. 

In  electrolytic  copper  refineries  the  slimes  are  usually 
treated  by  the  sulphuric  acid  method,  which  is  modified 


48  MODERN  ELECTROLYTIC  COPPER  REFINING. 

according  to  the  character  of  the  material.  In  ordinary  prac- 
tice the  wet  slimes  from  the  tank-room  are  dried  in  a  cen- 
trifugal dryer  having  3o-mesh  phosphor  bronze  screens  in 
place  of  the  usual  filter  cloth.  The  coarse  particles  of  copper 
are  caught  on  the  screen,  while  the  slimes  pass  through  into 
a  storage  tank.  In  this  treatment  about  10%  by  weight 
of  the  slimes  is  separated  as  metallic  copper  very  rich  in 
silver,  which  is  added  to  the  charge  in  the  anode  furnace. 
The  slimes  after  settling  are  transferred  to  a  large  tank 
lined  with  i2-lb.  lead  and  equipped  with  two  steam  coils 
extending  its  full  length.  Hot  air  is  forced  into  the  solu- 
tion by  an  injector.  Sulphuric  acid  in  the  proportion  of 
1500  Ib.  of  acid  (66°  B.)  per  ton  of  slimes  is  then  added  and 
the  solution  boiled  from  10  to  12  hours,  which  results  in 
the  dissolving  of  most  of  the  copper,  66%  of  the  arsenic 
and  all  of  the  bismuth  and  iron.  The  supply  of  steam  is 
then  shut  off  and  the  solution  allowed  to  settle.  The  super- 
natant liquor  very  rich  in  impurities  is  siphoned  into  storage 
tanks  and  subsequently  transferred  to  the  evaporators  for 
the  manufacture  of  copper  sulphate  crystals  (bluestone). 
The  tank  is  then  filled  with  water  up  to  the  level  of  the 
original  sulphuric  acid  solution,  the  steam  is  turned  on, 
and  the  temperature  again  raised  to  the  boiling  point. 
When  this  is  done  an  addition  is  made  of  the  settlings  from 
the  acid-parting  kettles,  which  consist  of  anhydrous  sul- 
phate of  copper  and  considerable  silver  sulphate,  and  the 
contents  of  the  tank  are  thoroughly  mixed.  The  copper 
precipitates  metallic  silver  from  the  silver  sulphate  solu- 
tion, being  itself  transformed  to  copper  sulphate,  and  the 
treatment  is  continued  until  metallic  silver  is  no  longer 
produced.  Should  the  silver  sulphate  be  in  excess  of  the 
corresponding  quantity  of  copper  needed  to  precipitate  its 
silver  content,  a  small  addition  of  untreated  slimes  is  made 
to  supply  the  deficiency.  The  slimes  are  then  washed 
several  times  by  decantation,  transferred  to  filters,  and 


DEVELOPMENT,    METHODS,  AND  APPARATUS.  49 

washed  with  boiling-hot  water.  They  are  then  transferred 
to  cast-iron  drying  pans  and  dried  in  a  furnace,  the  dried 
product  being  subsequently  mixed  with  sand  and  soda  ash 
and  melted  in  a  reverberatory  furnace  capable  of  holding 
100,000  oz.  of  silver.  The  dore  bars  resulting  from  the 
furnace  treatment  assay  from  950  to  960  fine  in  silver  and 
from  10  to  20  in  gold,  the  remainder  being  copper.  The 
slag  from  the  furnace  melting  contains  8%  or  10%  copper 
and  300  to  400  oz.  silver  per  ton,  the  quantity  produced 
depending  upon  the  richness  of  the  slimes.  If  the  slimes 
are  very  rich  the  quantity  of  slag  need  not  exceed  200  Ib. 
per  ton  of  slimes  treated.  The  dore  bars  are  placed  in  cast- 
iron  kettles  and  parted  by  sulphuric  acid  (66°  B.),  similarly 
to  the  process  in  use  at  the  New  York  Assay  Office  and  at 
other  government  refineries,  or  they  are  parted  electro- 
lytically  by  the  Moebius  or  the  Thum-Balbach  process. 

The  cement  silver  obtained  in  acid  parting  is  thoroughly 
washed  with  hot  water,  placed  in  a  hydraulic  press  and 
pressed  into  cakes  of  1500  to  2000  oz.  weight,  which  are 
removed  from  the  press  and  charged  without  drying  into 
a  refining  furnace  of  100,000  oz.  capacity.  A  small  quan- 
tity of  niter  is  thrown  on  the  metal  to  remove  the  tellurium 
contained  in  the  silver.  When  this  is  accomplished  the 
molten  refined  silver  is  cast  into  i2oo-oz.  molds.  The 
refined  metal  varies  from  998  to  998.5  in  fineness. 

The  gold  is  transferred  to  small  parting  kettles  and 
boiled  with  sulphuric  acid  (66°  B.)  to  dissolve  the  remain- 
ing silver.  When  this  is  accomplished  a  few  lumps  of  salt- 
peter are  added  to  the  solution  and  the  boiling  continued 
for  two  or  three  hours  to  remove  the  small  quantity  of 
silver  still  contained  in  the  gold  and  to  coagulate  the  finely 
dissolved  gold,  which  is  of  advantage  in  diminishing  the 
quantity  of  float  gold  produced  in  the  subsequent  washing. 
The  gold  is  then  dried,  melted  under  borax,  and  cast  into 
bars  of  993  to  996  fineness. 


50  MODERN  ELECTROLYTIC  COPPER  REFINING. 

Generally,  in  electrolytic  copper  refineries,  the  copper 
sulphate  solution  formed  by  the  reduction  of  the  silver 
sulphates  is  added  to  the  copper  electrolyte  in  order  to 
utilize  the  free  sulphuric  acid  which  is  present  to  the  extent 
of  from  8%  to  10%.  The  impure  solution  from  the  slimes 
tank  is  concentrated  by  evaporation  to  42°  B.  and  crys- 
tallized, the  crystals  formed  being  purified  by  repeated 
solution  and  crystallization  until  of  marketable  purity. 
The  mother  liquor  from  the  crystals  contains  about  40%. 
sulphuric  acid,  which  is  utilized  by  heating  in  a  lead  pan 
to  60°  B.  and  subsequent  cooling  in  iron  pans.  During 
the  cooling,  basic  salts  of  iron  and  copper  are  separated. 
The  resultant  acid  solution  is  used  either  in  parting  the 
dore  bars  or  in  the  first  treatment  of  the  slimes.  The  slags 
produced  in  refining  the  slimes  are  treated  in  several  ways: 
i.  By  addition  to  the  slags  from  the  anode  furnace,  which, 
however,  has  the  objection  that  the  resultant  copper  is 
very  impure  and  must  be  separately  treated  in  the  tank- 
room.  2.  By  treatment  in  a  shaft  furnace  with  litharge, 
which  yields  a  copper  matte  and  a  silver-lead  bullion.  The 
latter  is  cupelled  for  silver,  the  litharge  formed  being  used 
to  treat  another  lot  of  slime  slag.  3.  By  melting  the  slag 
with  lead  in  a  small  reverberatory,  as  at  the  Raritan  Copper 
Works.  4.  By  mixing  with  soda  ash  and  melting  in  a 
reverberatory  furnace,  which  yields  a  very  clean  slag  and 
a  very  base  bullion.  This  slag  is  sold  to  lead  smelters,  as 
it  contains  less  than  60  oz.  silver  per  ton  and  practically- 
all  of  the  antimony  and  tellurium  of  the  original  slimes. 
The  base  bullion  is  treated  by  adding  small  quantities  to 
the  regular  charge  of  the  softening  furnace.  The  last- 
named  method  is  the  one  used  at  the  present  time  by  the 
Seattle  Smelting  and  Refining  Co.,  at  Seattle,  Wash.,  in  the 
treatment  of  the  slimes  produced  by  the  Amalgamated 
Copper  Co. 's  plants  at  Great  Falls  and  at  Anaconda,  Mont. 


DEVELOPMENT,  METHODS,  AND  APPARATUS. 


RESUME    OF   MODERN    PRACTICE    IN    ELECTROLYTIC    WORKS. 

1.  Anodes:  Precious  metal  bearing  copper,  refined  to  as 
high  a  percentage  as  is  commercially  practicable,  say  96% 
to  99%  Cu. 

2.  Cathodes:    Thin   sheets   of   electrolytic   copper,    de- 
posited upon  and  stripped  from  greased  lead  or  copper 
plates. 

3.  Electrolyte:   Solutions  containing  not  less  than  12% 
and  not  over   20%  bluestone   (CuSO4+5H2O)   and  from 
4%  to  10%  free  sulphuric  acid.     It  is  very  important  that 
the  constantly  decreasing  acidity  and  the  constantly  in- 
creasing copper  contents  of  the  electrolyte  be  maintained 
within  these  limits.     A  small  quantity  of  salt    or  hydro- 
chloric acid  is  always  added  to  hinder  any  possible  solu- 
tion of  silver  and  to  prevent  "sprouting"  or  brittleness 
of  the  cathodes.     Ammonium  sulphate  is  sometimes  added 
when  considerable  arsenic  is  present. 

4.  Temperature:  Heating  the  electrolyte  up  to  between 
40°  and  50°  C.  is  advantageous,  because  it  decreases  the 
electrical  resistance  of  the  solution  and  increases  the  ten- 
sile strength  of  the  depositing  copper.     It  is  essential  to 
maintain  the  temperature  as  evenly  as  possible  at  the  point 
fixed  upon,  and  to  avoid  appreciable  differences  in  tem- 
perature between  the  upper  and  lower  portions  of  the 
solution. 

5.  Current  Density:   From  4  to  45  amperes  per  square 
foot    of    cathode    surface,   according  to  the  cheapness  of 
power,  the  grade  of  the  anodes  in  silver  and  impurities,  and 
the  purity  of  the  electrolyte. 

6.  Voltage:  o.i  to  0.3  V.,  according  to  the  current  den- 
sity, composition  of  the  anodes  and  electrolyte,  tempera- 
ture,  structure   of   the  electrodes,   and  the  distance  the 
latter  are  placed  apart. 


$2  MODERN  ELECTROLYTIC  COPPER  REFINING. 

7.  Products  of  Refining: 

(a)  Cathode  copper  (99.86%'  to  99.94%  Cu),  the 

yield  being  from  97%  to  99%  of  the  copper 
contained  in  the  anodes  refined  (barring  the 
anode  scrap),  and  i%  to  3%  of  the  copper 
being  recovered  as  bluestone. 

(b)  Fine  silver,  -} 

(c)  Fine  gold,  I  obtained  from 

(d)  Base  bullion,  containing  anti-  |       t1he     anode 

1  j_  n     •  slimes, 

mony,  arsenic,  and  tellurium,  J 

(e)  Bluestone,  \  obtained  both   from 
(/)  Impure  arsenical  copper,  j-      the    anode    slimes 
(g)  Arsenious  acid,  )      and  the  electrolyte. 
(h)  Nickel  vitriol,  obtained  from  concentrated  elec- 
trolytic solutions. 


TABLES  GIVING  OUTPUTS  AND  OTHER  DATA  OF  ELECTROLYTIC 
COPPER   REFINERIES. 

The  subjoined  carefully  compiled  statistical  tables  show 
that  the  world's  average  production  of  electrolytic  copper 
is  now  about  883  short  tons  daily,  of  which  764  tons,  or 
86.5%,  are  supplied  by  the  United  States.  Of  the  balance 
of  the  world's  production  of  about  119  tons  daily  or  ap- 
proximately 13.5%,  Great  Britain  produces  a  little  over 
8.8  %,  Germany  about  2. 75  %,  and  France  a  little  over  i  .6  %. 

The  United  States  now  produces  at  the  enormous  rate 
of  278,860  tons  of  electrolytic  copper,  which  at  $260  per  ton 
is  worth  $72,503,600,  annually.  The  by-product  recov- 
ered daily  contains  about  74,100  oz.  silver  and  948  oz. 
gold,  which  equals  an  annual  output  of  over  twenty-seven 
million  ounces  of  silver,  valued  at  nearly  $13,000,000,  and 
more  than  three  hundred  and  forty-six  thousand  ounces 
of  gold,  valued  at  $7,152,233. 

According  to  the   Treasury   Bureau  of  Statistics,   the 


DEVELOPMENT,  METHODS,  AND  APPARATUS. 


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DEVELOPMENT,  METHODS,    AMD  APPARATUS.  55 

•copper  exports  of  the  United  States,  chiefly  consisting  in 
electrolytic  copper,  for  the  year  1902,  alone  represented  a 
value  of  $45,485,598,  as  against  $33,534,899  in  1901,  and 
were  only  exceeded  in  value  by  the  country's  exports  of 
manufactures  of  iron  and  steel  and  of  mineral  oils. 

There  are  now  in  active  operation,  or  ready  to  be  placed 
in  commission,  33  electrolytic  copper  refineries  in  the 
world,  not  including  the  plant  of  the  Osaka  Electrolytic 
.Refining  Co.,  now  being  constructed  at  Osaka,  Japan. 


CHAPTER  II. 

DESCRIPTION    AND    VIEWS    OF    ELECTROLYTIC    COPPER 
REFINING  WORKS. 

THE  present  practice  and  appliances  used  in  electro- 
lytic copper  works  are  described  in  detail  in  the  following 
pages,  and  the  characteristic  arrangements  of  plant  and 
the  equipment  are  illustrated,  wherever  it  has  been  possi- 
ble to  obtain  views,  in  order  to  give  the  reader  a  fair  and 
comprehensive  conception  of  the  present  status  and  mag- 
nitude of  electrolytic  copper  refining. 

The  works  are  grouped  under  the  heads  of  the  coun- 
tries in  which  they  are  situated,  starting  with  the  United 
States  and  followed  in  order  by  Great  Britain,  Germany, 
Austro-Hungary,  France,  and  Russia,  and  under  each  head 
the  refineries  are  considered  in  the  order  of  their  relative 
capacities. 

Not  including  the  plant  of  the  Osaka  Electrolytic 
Refining  Co.,  in  Japan,  which  is  reported  to  be  under 
construction,  they  embrace  a  total  of  33  refineries. 

A.    UNITED  STATES. 

I.  The  Raritan  Copper  Works.* 

By  LAWRENCE  ADDICKS. 

The  Raritan  Copper  Works,  in  its  location  at  Perth 
Amboy,  N.  J.,  possesses  unusual  advantages  for  the  econom- 

*  Taken  from  The  Mineral  Industry,  vol.  ix,  by  kind  permission  of  the 
author  and  publishers. 

56 


'  I    I     T 

DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  57 

ical  refining  of  copper.  The  transportation  facilities  are 
such  that  the  most  favorable  freight  rates,  both  domestic 
and  foreign,  are  obtainable  and  the  proximity  of  New 
York  allows  the  lowest  prices  on  supplies  to  be  procured. 
Spurs  from  the  Pennsylvania  Railroad,  the  Central  Rail- 
road of  New  Jersey,  and  the  Lehigh  Valley  Railroad  run 
directly  into  the  yards  of  the  works,  and  a  private  line  of 
lighters  is  maintained  from  the  company  wharf,  a  short 
distance  from  the  furnace  building,  to  New  York  by  way 
of  Staten  Island  Sound.  The  lighters  afford  a  cheap  means 
of  placing  the  refined  product  alongside  outward-bound 
vessels  at  New  York  and  the  competition  among  the  differ- 
ent railways  precludes  the  possibility  of  the  company  ever 
being  placed  at  the  mercy  of  a  single  line.  There  is  suffi- 
cient depth  of  water  at  the  wharf  to  allow  large  vessels 
to  load  and  unload  directly  at  the  works  should  it  be  found 
desirable. 

The  plant  was  designed  for  a  maximum  monthly  produc- 
tion of  from  10,000,000  to  12,000,000  Ib.  of  cathode  copper 
in  the  tank-house  and  from  15,000,000  to  18,000,000  Ib.  of 
refined  copper  from  the  furnaces.  The  output  of  precious 
metals  varies  with  the  character  of  material  treated,  but 
may  be  stated  as  300,000  oz.  of  silver  and  5000  oz.  of  gold 
per  month.  A  very  wide  range  of  raw  material  is  treated, 
about  the  only  requirement  being  that  the  copper  content 
shall  be  equal  to  that  of  good  blister  copper.  The  excess 
of  furnace  capacity  over  tank-house  capacity  makes  it 
possible  to  treat  a  considerable  quantity  of  outside  cathodes. 
Anodes  from  outside  sources  also  are  more  or  less  handled. 

General  Plan. — The  general  arrangement  of  the  build- 
ings and  railroad  connections  is  shown  on  the  accompany- 
ing ground  plan  (Fig.  16),  which  is  self-explanatory.  The 
standard-gauge  tracks  connecting  with  the  several  railway 
systems  are  indicated  by  heavy  lines,  while  the  narrow- 
gauge  tracks  of  the  industrial  railroad,  as  it  is  called,  are 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


MAP  OF  THE 

RARITAN  COPPER  WORKS 

Perth  Amboy,  N.  J. 

Dec.  1900 


Office 

Sulphate  Bld'g 
C    Silver  Bld'g 
D    Smithy 
E    Machine  Shop 
F    Stores 
G    Power  House 
H    Pump  House 
I    Tank^Hous* 
J    Furnace  House 
K    Lavatory 
L    Coal  Storage 
M    Engine  House 
N    Furnace  House 
O    Blast  Furnace 
P    Storage  Bld'g 
-Industrial  R.R. 
Standard  Gauge  R.R. 


FIG.  16. 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  59 

distinguished  by  light  lines.  This  railroad  is  equipped  with 
two  locomotives  and  a  large  number  of  iron  flat  cars  of  a 
capacity  of  10  tons  each,  and  it  binds  all  the  buildings 
together  with  a  network  of  tracks.  All  incoming  copper 
bullion  is  unloaded  from  the  freight  cars  directly  on  these 
small  ones  and  taken  to  the  storage  building,  where  it  is 
weighed,  without  being  removed,  in  drafts  of  about  15,000 
Ib.  Ample  yard  tracks  are  provided,  so  that  such  material 
as  is  not  for  immediate  use  may  be  temporarily  stored  on 
the  cars,  thus  avoiding  subsequent  rehandling 

The  greatest  care  is-  used  to  obtain  accurate  weights. 
Two  scales  are  provided  and  all  material  is  weighed  twice. 
Furthermore  there  are  two  weigh-masters  who  keep  inde- 
pendent records,  while  a  third  man  checks  the  number  of 
pieces.  The  scales  were  installed  by  the  Fairbanks  Co., 
and  their  representative  makes  weekly  visits  to  the  works 
to  examine  and  adjust  them.  For  further  reassurance 
that  they  are  in  perfect  adjustment  a  car  loaded  with 
standard  weights  is  run  on  several  times  a  day.  Heavy 
sampling  drills  and  a  coffee-mill  are  also  provided  in  the 
storage  building. 

The  works  proper,  shown  by  the  dotted  fence  line  on 
the  map,  cover  about  45  acres.  The  various  buildings  are 
grouped  about  the  tank-house  as  a  center  and  all  are  so 
arranged  that  future  extensions  may  be  made  with  the 
least  possible  expense  and  inconvenience.  A  coal- storage 
building  is  conveniently  placed  near  the  power-house,  and 
a  coal  trestle  to  supply  the  furnaces  is  located  at  the  oppo- 
site side  of  the  grounds. 

The  general  use  of  steel  construction  throughout  the 
plant,  the  thorough  fire  protection,  and  the  universal  appli- 
cation of  labor-saving  machinery  are  noteworthy  features. 
The  three  furnace  buildings  are  entirely  of  metal  and  need 
no  special  fire  protection.  The  tank-house  has  a  steel 
skeleton  with  brick  curtain  walls  and  is  protected  by  a 


60  MODERN  ELECTROLYTIC  COPPER  REFINING. 

thorough  system  of  automatic  sprinklers  and  eight  inside 
hose  connections.  The  other  main  buildings  are  protected 
by  sprinklers.  The  coal- storage  building  is  provided  with 
a  number  of  thermostats  buried  in  the  coal  heaps.  For 
fire  service  an  Underwriter  pump  of  a  capacity  of  1000  gal. 
per  minute  is  kept  in  constant  readiness  to  be  thrown  on 
full  head  at  an  instant's  notice.  The  water  supply  con- 
sists of  an  8-in.  city  main,  a  24-in.  line  from  the  river,  two 
wells,  and  a  reservoir.  In  an  emergency  a  portion  of  the 
regular  pumping  system  may  also  be  pressed  into  fire  ser- 
vice. A  number  of  fully  equipped  hose  houses  and  a 
thoroughly  organized  fire  department  complete  the  pro- 
tective measures. 

In  passing  it  may  be  of  interest  to  state  that  the  ground 
was  broken  for  the  erection  of  the  first  building  on  August 
i,  1898,  and  the  current  was  turned  on  in  the  tank-house 
March  23,  1899,  an  interval  of  less  than  eight  months. 

Office  Building. — The  office  building  is  two  and  one-half 
stories  high  and  about  75X90  ft.  Here  are  located  the 
general  offices,  the  drafting-room,  and  the  chemical  and 
physical  laboratories.  The  chemical  laboratory  is  divided 
into  three  rooms,  the  assay-room,  the  balance -room,  and 
the  general  laboratory.  The  assay-room  is  equipped  with 
three  gas  muffie  furnaces,  a  gas  crucible  furnace,  a  rolling 
machine,  a  cupel  machine,  pulp  balance,  bucking-board,  etc. 
The  balance -room  contains  a  set  of  five  gold,  analytical, 
and  pulp  balances,  supported  on  a  special  foundation  to 
avoid  vibration.  The  general  laboratory,  which  is  about 
20X35  ft.,  is  furnished  with  the  customary  gas,  water, 
electricity,  suction,  hoods,  etc.  A  unique  feature  is  the 
use  of  electric  heaters  as  hot  plates  in  the  hoods.  On  the 
opposite  page  is  tabulated  the  routine  work  of  the  labora- 
tory. 

There  are  also  special  determinations  occasionally  made, 
as  analyses  of  coal,  water,  etc.,  and  the  copper,  arsenic, 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS. 


61 


and  antimony  contents  in  wire  bars  in  the  event  of  a  low 
conductivity  report  by  the  physical  laboratory,  but  these 
are  of  comparatively  infrequent  occurrence.  For  details 
of  the  methods  of  analysis  employed,  the  reader  is  referred 
to  the  article  on  copper  analysis  by  Titus  Ulke,*  the  meth- 
ods there  described  agreeing  closely  with  those  employed 
here. 


Frequency. 

Material. 

Determinations. 

Twice  daily     

Blast-furnace  slag          .  . 

Cu 

r  Electrolyte  (a)  

Cu,  Acid,  Sp.  Gr. 

Daily.  . 

Copper  bullion  

Cu,  Ag,  Au. 

r»       A        A 

Anodes  

Blast-furnace  pigs 

Cu,  Ag,  Au. 
Cu  Ag  Au 

Cathodes     

Cu  Ag  As  Sb. 

Electrolyte     

Cu  As  Sb,  Cl. 

Slimes          

Cu  Ag,  Au. 

Weekly       

. 

Silver  slabs     

Ag,  Au. 

Silver  slag  

Cu,  Ag,  Au,  Pb 

Fine  silver  

Ag. 

Au. 

Blister  slag  '. 

Cu,  Ag,  Au. 

Refinery  slag 

Cu 

Occasionally  

Blast-furnace  charge.  .  .  . 
Cement  copper  

Cu,  Ag,  Au,  SiO2,  Fe,  CaO. 
Cu,  Ag,  Au. 

(a)  Performed  at  laboratory  in  tank-house,  but  included  here  for  the  sake  of  completeness. 

The  physical  laboratory  is  equipped  with  a  Queen  .con- 
ductivity bridge,  a  6ooo-lb.  Riehle  tensile  machine,  and  a 
5oo-lb.  Riehle  torsional  wire -testing  machine.  Daily  tests 
are  made  of  the  conductivity  of  each  lot  of  copper  produced 
by  the  refining  furnaces,  whether  ingots,  wire  bars,  or 
cakes.  The  bridge  is  checked  each  day  against  a  standard. 
No.  12  B.  &  S.  annealed  wire  is  used  for  these  conductivity 
tests ;  it  is  drawn  in  the  shops  from  small  sample  bars  taken 
from  each  charge.  The  written  approval  of  the  physical 
laboratory  is  required  before  any  lot  is  allowed  to  leave 
the  works. 


*  Engineering  and  Mining  Journal,  Dec.  16,  1899. 


62 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


Power-house. — The  power-house  is  of  modern  design, 
built  of  brick  and  steel.  It  is  divided  by  a  central  longi- 
tudinal brick  partition  into  boiler-  and  engine-rooms.  The 
general  arrangement  is  clearly  shown  in  the  sectional  draw- 
ing (Fig.  17).  The  building  is  thoroughly  fireproof,  and 
in  this  connection  it  may  be  noted  that  the  engine-room 
floor  is  constructed  on  the  Ransome  system  of  cement 


FIG.  17. — Cross-section  of  Power-house. 

throughout.     A  basement  9  ft.  in  the  clear  is  provided 
beneath  the  engine-room. 

The  boiler-room  contains  the  boiler  equipment  only, 
consisting  of  eight  400-H.P.  and  two  200-H.P.  Babcock  & 
Wilcox  water-tube  boilers.  These  are  set  in  pairs,  with  a 
passageway  between  each  battery  for  the  convenient  blow- 
ing of  tubes  and  cleaning  of  dust-chambers.  The  furnaces 
are  of  the  Murphy  automatic-stoking  type.  Directly  be- 
neath them  is  an  ash-tunnel  running  the  length  of  the 
building;  through  this  tracks  are  laid  for  a  side-dumping 


DESCRIPTION  AND  VIEWS  OF  REFINING   WORKS.  63 

steel  car.  Under  each  furnace  is  a  steel  hopper  the  dimen- 
sions of  which  correspond  to  the  capacity  of  the  car,  fur- 
nished with  a  sliding  gate  at  the  bottom.  When  the  car 
is  placed  in  position,  this  gate  is  opened,  the  ashes  are 
dumped,  and  the  car  is  pushed  through  the  tunnel  to  a 
hydraulic  lift  at  the  south  end  of  the  building,  raised  to 
grade  and  run  out  to  the  lowlands  for  dumping.  Over 
the  furnaces  is  a  coal  hopper  of  393  tons  capacity,  extend- 
ing the  length  of  the  boiler-room,  with  a  discharge  nozzle 
over  each  feeding  magazine.  At  the  end  of  each  nozzle 
is  a  swinging  gate  with  lever  and  rod  connection  extending 
down  to  the  front  of  the  furnaces  within  easy  reach  of  the 
firemen.  Directly  beneath  each  nozzle  is  hung  a  heavy 
sheet-iron  chute  of  13  cu.  ft.  capacity,  at  the  lower  end 
of  which  is  another  swinging  gate  controlled  with  lever 
and  rod  as  before.  These  chutes  and  levers  are  shown  in 
the  photograph  of  the  boiler-room  (Fig.  18).  There  are 
two  furnaces  to  each  boiler  and  one  double  and  two  single 
magazines  to  each  pair  of  furnaces.  The  upper  gate  levers 
are  connected  to  a  counter  in  such  a  manner  that  the  num- 
ber of  chutes  of  coal  used  for  each  boiler  is  registered,  thus 
allowing  the  coal  consumption  readily  to  be  computed. 

The  coal  is  handled  mechanically  throughout  its  entire 
course,  being  dumped  from  the  cars  in  which  it  is  shipped 
into  a  hopper,  then  taken  by  a  drag  conveyor,  screened, 
the  coarse  lumps  crushed,  recombined  with  the  screenings, 
and  elevated  to  the  tower  of  the  coal-storage  building  just 
south  of  the  power-house.  From  this  tower  it  may  be  con- 
veyed either  to  the  bins  of  the  coal-storage  building  or 
directly  to  the  hopper  in  the  boiler-room.  The  space 
beneath  each  boiler  where  the  grates  and  ash-pits  are 
usually  placed  is  used  entirely  as  a  combustion-chamber 
.and  for  the  collection  of  the  heavier  ash  and  soot  which  is 
carried  through  from  the  furnaces.  The  smoke-flue  is  built 
-as  a  tunnel  parallel  with  the  ash-tunnel,  and  leads  to  a  brick 


64  MODERN  ELECTROLYTIC  COPPER  REFINING. 

stack  175  ft.  high,  at  the  south  end  of  the  building.  There 
are  individual  dampers  arranged  for  hand  control  and  a 
main  damper  governed  by  a  Spencer  damper-regulator. 
The  north  boilers  are  used  for  electrolytic  service,  while 
the  three  south  boilers  are  used  independently  for  supply- 
ing steam  for  solution  heating  in  the  tank-house  and  for 
operating  the  general  service -pumps  and  the  light  and 
power  engines.  These  latter  boilers  are  operated  at  125- 
Ib.  and  the  former  at  i7o-lb.  gauge  pressure. 

The  illustration  of  the  power-house  (Fig.  17)  and  the 
photograph  (Fig.  19)  show  the  general  arrangement  of  the 
main  piping.  The  steam -header  is  shown  in  section  near 
the  division  wall.  The  valves  allow  a  boiler  to  feed  its  own 
engine  directly  or  to  supply  the-  main  header  in  parallel 
with  the  other  boilers  as  occasion  may  demand.  With  this 
system  it  is  possible  to  repair  the  entire  steam-header  with- 
out interruption  of  the  service  or  in  turn  to  repair  any  one 
of  the  steam  mains  without  discontinuing  the  service  for 
more  than  one  unit.  A  separator  is  inserted  between  the 
header  and  each  throttle -valve.  The  engines  for  the  elec- 
trolytic service,  five  in  number,  are  vertical,  cross-com- 
pound, and  condensing,  running  at  150  revolutions  per 
minute,  each  direct  connected  to  its  generator.  The  dif- 
ferent generators  vary  slightly  in  capacity,  but  the  largest, 
built  by  the  General  Electric  Co.,  deliver  4500  amperes  at 
an  efficiency  of  93.5%.  The  engines  for  supplying  light 
and  general  power  are  horizontal,  tandem -compound,  run- 
ning at  265  revolutions  per  minute,  with  generators  direct 
connected.  All  of  the  engines  were  built  by  the  Ball  & 
Wood  Co.  Efficiency  tests  of  the  vertical  Corliss  engines 
showed  an  economy  of  from  13.4  to  13.7  Ib.  of  steam  per 
I.H.P.  per  hour.  The  exhaust  piping  of  the  engines  leads 
from  the  gallery  down  past  the  generators,  through  the 
floor  to  Berryman  feed-water  heaters  and  thence  to  Bulkley 
ejector  condensers.  Each  engine  has  its  independent  in- 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  65 

termediate  heater  and  condenser.  The  boiler  feed-water 
passes  from  the  city  main  through  a  meter  in  the  north 
end  of  the  power-house  basement  into  a  main  running  the 
full  length  of  the  building  and  tapped  at  each  of  the  Berry- 
man  heaters.  A  parallel  main  receives  the  discharge  from 
the  heaters  and  carries  it  to  a  Cochrane  open  heater  set 
directly  above  the  feed-pumps  at  the  south  end  of  the  build- 
ing. The  exhausts  from  the  light  and  power  engines  and 
boiler-feed  and  general  service  pumps  are  taken  into  this 
heater.  The  Berryman  heaters  deliver  the  feed-water  at 
123°  F.  and  the  Cochrane  heater  raises  this  temperature  to 
about  210°  F.  The  feed- water  is  carried  into  the  feeding 
main  by  duplex,  tandem-compound  Snow  pumps.  The 
branch  for  each  boiler  is  provided  with  a  Worthington  hot- 
water  meter  and  a  specially  graduated  throttling-valve. 
Suitable  thermometer  wells  and  boiler  oil  injectors  are 
placed  in  each  boiler  feed-pipe  within  easy  reach  and  con- 
trol of  the  engineer;  the  feed-pipes  do  not  pass  through 
the  division  wall  into  the  boiler-room  until  after  leaving 
the  hot-water  meters.  A  valve  in  the  feed-line  is  also 
placed  in  the  engine-room  so  that  the  engineer  may  con- 
trol the  supply  of  water  if  he  so  desires.  Water-column, 
gauge-cocks,  and  steam-gauge  for  each  boiler  are  placed 
along  the  division  wall  on  the  engine-room  side,  the  piping 
leading  directly  through  the  wall  to  the  drums  of  the  boilers. 
There  are  also  draft  and  pyrometer  tubes  in  this  wall  at 
the  rear  of  each  boiler.  In  this  way  the  engineer  has  the 
boiler  performance  entirely  under  his  observation  and  con- 
trol without  going  into  the  boiler-room. 

At  the  extreme  south  end  of  the  power-house  is  the 
pumping  plant.  It  consists  of  two  centrifugal  pumps 
which  take  water  for  condensing  purposes  from  a  well  fed 
by  the  river,  two  24 -in.  stroke  3,ooo,ooo-gal.  compound 
duplex  pumps  which  are  used  expressly  for  supplying  bosh 
water  to  the  copper  furnaces  on  a  return  system,  including 


€6  MODERN  ELECTROLYTIC  COPPER  REFINING. 

the  reservoir,  a  35o,ooo-gal.  compound  duplex  pump  used 
for  supplying  water  for  general  purposes  about  the  works, 
and  the  simple  duplex  Underwriter  pump  before  men- 
tioned, which  ordinarily  supplies  a  number  of  hydraulic 
lifts.  Two  Westinghouse  9-5-in.  air-pumps  supply  air  at 
70  Ib.  pressure  for  cleaning  generators,  handling  oil,  acid, 
«tc.,  and  for  operating  pneumatic  hoists. 

The  oiling  system  for  the  entire  plant  is  a  modification 
of  the  usual  gravity  system.  A  reservoir  is  placed  at  one 
end  of  the  engine-room  directly  beneath  the  roof  and  is 
connected  by  suitable  piping  with  the  sight-feed  and  con- 
trolling valves  which  distribute  oil  to  the  various  bearings. 
All  of  the  valve-motion  mechanism  is  lubricated  with  grease 
from  compression  cups.  The  engines  are  specially  fitted 
with  oil-ways,  collecting-rings,  and  guards,  and  the  waste 
oil  is  carefully  caught  and  piped  to  a  fire-proof  oil -room 
in  the  basement  In  this  oil-room  there  are  two  sets  of 
filters  and  a  receiving-tank  from  which  the  overhead  tank 
is  periodically  filled.  Compressed  air  is  used  for  refilling 
the  overhead  gravity  tank  and  a  counter  attached  .to  a 
float  registers  the  number  of  tanks  of  oil  used.  The  valves 
and  pistons  of  the  engines  are  lubricated  by  means  of  Ster- 
ling, Jr.,  pumps  There  is  a  pump  connected  with  each 
admission  valve,  operated  by  the  exhaust- valve  mechan- 
ism in  such  a  manner  that  a  minute  quantity  of  oil  is  injected 
into  the  steam  just  prior  to  its  admission  to  the  cylinder  at 
each  stroke. 

Tank-house. — The  electrolytic  plant  is  in  a  single  build- 
ing approximately  200  X  600  ft.  The  use  of  a  steel  skeleton, 
carrying  the  loads,  and  brick  curtain  walls,  and  the  7  to  8  ft. 
of  head  room  in  the  basement  are  noteworthy  features  in 
the  construction.  The  type  of  building  is  show^n  in  the 
illustration  (Fig.  20)  and  the  photograph  (Fig.  21).  Thor- 
ough lighting  and  ventilation  are  supplied  by  an  immense 
number  of  windows,  a  large  high  monitor,  and  a  series  of 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS. 


ventilating  skylights.  The  main  floor  is  made  very  heavy 
and  can  support  a  loaded  train  in  connection  with  the  indus- 
trial railroad.  The  basement  is  floored  with  a  6-in.  layer 


FIG.  20. — Cross-section  of  Tank-house. 

of  tar  concrete  which  has  proved  very  satisfactory  in  with- 
standing acid  and  trucking.  There  is  a  5 -ply  tar  and  gravel 
roof,  the  planking  of  which  is  carried  on  steel  trusses.  The 
general  ground  plan  is  shown  diagrammatically  in  Fig.  22. 


150 
Tanks 


50 
Tanks 


PcjaP 


50 
Tanks 


50 
Tanks 


GROUND  PLAN 

Q,  OFFICE.     L,  LABORATORY.     P,P,  PUMPS.     TOTAL  NOMBtR  OF  TANKS,  l»600t 

FIG.  22. — Tank-house. 

An  office  and  laboratory  are  provided  at  one  end  while  the 
main-floor  space  is  given  up  to  the  1600  depositing  tanks. 
The  liberating  tanks,  32  in  all,  are  in  small  additions  built 
on  the  north  side.  Emery-wheels,  punches,  and  shears 
are  placed  along  the  end  walls,  and  the  solution  pumps 
are  situated  in  the  main  longitudinal  aisle.  Tunnels  are 
provided  from  the  basement  to  the  power-house  and  silver 
buildings.  Four  electric  cranes  equipped  with  a  special 
appliance  for  handling  electrodes  run  the  length  of  the 
building,  each  commanding  400  tanks.  For  convenience 


68  MODERN  ELECTROLYTIC  COPPER  REFINING. 

in  description  the  tank-house  may  be  considered,  first, 
from  the  point  of  mechanical  operation,  second,  from  that 
of  electrical  supply,  and  third,  from  that  of  distribution 
of  electrolyte. 

Operation. — The  regulation  multiple  system  is  in  use, 
the  tanks  being  electrically  in  series  and  the  electrodes  in 
each  tank  in  parallel.  This  necessitates  the  apportionment 
of  a  certain  number  of  tanks  as  cathode-forming  or  *  *  strip- 
ping "  tanks.  These,  180  in  all,  are  divided  between  the  two 
end  sections,  giving  ready  access  to  the  special  machinery 
along  the  end  walls.  The  cathodes  in  these  tanks  are 
rolled  plates  of  pure  copper,  0.156  in.  thick,  the  surfaces 
of  which  have  been  smeared  with  tallow  which  is  kept  fluid 
in  steam- jacketed  pots.  These  are  used  as  a  basis  on  which 
to  form  the  thin  cathode  sheets  for  use  in  the  regular  de- 
positing tanks.  The  edges  are  protected  from  deposition 
by  grooved  wooden  strips  *  which  are  slipped  on  before  the 
plates  are  put  in  position.  After  remaining  in  the  strip- 
ping tanks  36  hours,  they  are  removed,  the  wooden  edges 
knocked  off,  and  the  thin  sheet  of  deposited  copper  peeled 
from  each  side  of  the  plate,  the  presence  of  the  tallow  hav- 
ing prevented  any  firm  adhesion  of  the  surfaces.  The 
entire  work  of  removing,  stripping,  and  replacing  a  plate 
occupies  but  a  few  moments.  The  thin  cathode  sheets  are 
taken  to  the  shearing  and  punching  machines,  where  two 
thin  copper  loops  are  riveted  on.  They  are  then  flattened 
carefully  out  by  beating  with  wooden  paddles  and  hung 
in  the  depositing  tanks  from  copper  rods  which  are  flattened 
at  one  end  to  prevent  rolling.  At  the  end  of  seven  days, 
the  cathodes  are  removed,  a  tankful  at  a  time,  by  the 
crane  and  dumped  on  the  floor  in  one  of  the  main  cross 
aisles.  The  rods  are  taken  out  and  the  cathodes  piled  on 

*  These  are  no  longer  in  use,  as  their  purpose  is  better  served  by  perfor- 
ating or  grooving  the  plates  near  their  lateral  and  bottom  edges  and  filling 
these  perforations  or  grooves  with  a  suitable  insulating  material. — TITUS  Ui*KB. 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS. 


69 


cars  of  the  industrial  railroad  to  be  taken  to  the  furnaces. 
The  shape  and  method  of  support  of  the  electrodes  may  be 
seen  in  the  drawing  illustrating  the  details  of  tank  con- 
struction (Fig.  23).  The  anodes  are  brought  into  the  tank- 


copper 


Glass  Block 


"PoFcelain  Block 


SIDE  ELEVATION 


CROSS  SECTION,  SHOWING 
METHOD  OF  ANODE  AND 
CATHODE  SUSPENSION 


«  n 

"1 

— 

v 

m      t^     v^  ^ 

jj 

1 

| 

—  Cathodes 
0 

! 

~  , 

&4                                                      :                                           ,                       Jp 

r 

_ 

^Copper.  Plate 
0 
^Anodes 

j 

• 

y           &          £,    ^ 

m     ka 

PLANi  SHOWING  ELECTRICAL  CONNECTIONS  BY  THE  DASHED  LI N.ES 

FIG.  23. — Details  of  Tank  Construction 

house  on  cars  and  hung  in  frames  made  of  structural  iron, 
which  are  designed  to  place  the  anodes  in  the  same  relative 
position  that  they  are  to  occupy  in  a  tank.  When  a  suffi- 
cient number  to  fill  one  tank  have  thus  been  hung,  the 
traveling  crane  picks  them  up  without  touching  the  frame 
and  carries  them  to  the  tank  in  question,  lowering  them 
directly  into  place  without  any  intermediate  handling  by 
the  men.  The  crane  is  shown  in  action  in  the  photograph 
of  the  tank-house  (Fig.  21).  Each  anode  weighs  about 
400  lb.,  and  as  there  are  22  to  a  tank,  the  load  weighs 
between  4  and  5  tons.  In  addition  to  the  cranes,  runways 
are  provided  over  each  separate  row  of  tanks,  along  which 
trolleys  travel  that  carry  differential  blocks  for  the  con- 
venient handling  of  single  electrodes.  These  find  constant 


70  MODERN  ELECTROLYTIC  COPPER  REFINING. 

use  in  connection  with  the  stripping  tanks.  The  anodes 
remain  in  the  tanks  43  days  on  an  average,  when  they  are 
taken  out,  scrubbed,  and  sent  back  to  the  anode  furnaces 
as  scrap.  By  careful  reworking  in  the  tanks  all  anodes 
the  condition  of  which,  on  removal,  warrants  the  labor  of 
rehandling,  the  percentage  of  this  scrap  returned  to  ,the 
furnaces  is  kept  down  to  about  9%.  The  slimes  are  re- 
moved but  once  in  three  months.  Then  the  tanks  are 
emptied  of  solution  one  at  a  time  by  means  of  steam  siphons. 
The  slimes  are  sluiced  through  an  outlet  in  the  tank  bottom 
into  barrels  mounted  on  trucks  in  the  cellar  below. 

Electrical  Supply. — Electrically  the  tank-house  is  divided 
into  units  of  400  depositing  and  8  liberating  tanks  each. 
These  408  tanks  are  all  connected  in  series  and  form  the  load 
of  one  of  the  large  generators  in  the  power-house.  There 
are  22  anodes  and  23  cathodes  in  multiple  in  each  tank. 
The  arrangement  of  tanks  in  pairs  with  cross  connections, 
as  shown  in  the  diagram  of  electrical  connections  (Fig.  23), 
combines  convenience  in  handling  with  economical  use  of 
copper  in  conductors  and  minimum  impairment  of  effi- 
ciency in  event  of  short  circuit  occurring  between  a  pair 
of  electrodes.  The  main  conductors  are  1.25X4  in.  bar 
copper,  carrying  about  4000  amperes.  The  connections 
between  paired  tanks  are  made  by  means  of  strips  of  copper. 
All  contact  resistances  are  kept  as  low  as  possible  by  the 
liberal  use  of  emery.  This  gives  a  current  density  of  15 
amperes  per  square  foot  of  cathode  surface,  the  end  elec- 
trodes being  credited  with  but  one  active  side  each.  Dur- 
ing cleaning,  a  tank  is  short  circuited  by  use  of  the  wedge 
or  key  shown  in  the  drawing  (Fig.  23).  The  conductors 
are  supported  by  five  clamps  on  each  tank,  three  of  which 
are  carried  down  to  the  stringers  below.  The  tanks  are 
insulated  from  the  building  with  the  greatest  care,  glass 
blocks  being  used  under  all  supports,  and  the  main  floor 
having  a  clearance  of  several  inches.  Bulging  at  the  sides 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  7* 

is  prevented  by  the  alleyway  floors  and  iron  braces  on  the 
outside  tanks. 

Distribution  of  Electrolyte. — Each  of  the  electrical  units 
mentioned  above  is  divided  into  two  circulations,  each  con- 
sisting of  200  depositing  tanks,  four  liberating  tanks,  a 
solution  well,  and  a  pump.  Thus  there  are  in  all  eight 
entirely  independent  circulations.  The  ground  plan  of  the 
tank-house  (Fig.  22)  shows  the  way  in  which  these  units 
are  placed  in  the  building,  each  pump  supplying  four  of 
the  5o-tank  squares  as  indicated  by  the  arrows.  These 
units  are  terraced  in  each  direction  as  shown  in  the  diagram 
(Fig.  24).  The  solution  is  carried  from  the  supply-box 


U      Well 

FIG.  24. — System  of  Circulation  of  Electrolyte. 

at  the  pump  along  a  main  and  supplies  the  tiers  in  multiple, 
so  that  each  ounce  of  solution  does  duty  in  five  tanks  in 
series  before  being  returned  to  the  solution  well  to  be 
pumped  up  again.  The  rate  of  circulation  is  controlled 
by  the  throw  of  the  pump,  which  is  of  the  plunger  type; 
at  the  rate  maintained,  all  the  solution  in  a  tank  is  replaced 
about  every  hour  and  three-quarters.  The  distribution  is 
governed  by  valves  at  the  crest  of  each  tier.  The  spouts 
from  tank  to  tank  take  the  solution  from  the  bottom  of  one 
tank  and  deposit  it  on  the  top  layer  of  the  next,  thus  main- 
taining a  uniform  density.  The  tanks  are  lined  throughout 
with  8-lb.  lead,  the  launders  with  6-lb.,  and  the  solution  well 
with  i4-lb.  A  certain  portion  of  the  solution  is  taken  from 
the  supply-box  at  the  pump  through  a  small  pipe  leading 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


to  the  liberating  tanks  and  thence  returned  to  the  well. 
These  liberating  tanks  serve  to  regulate  the  copper  content 
of  the  electrolyte.  They  are  identical  with  the  depositing 
tanks  in  construction  and  operation  except  that  lead  anodes 
are  used.  Their  location,  in  small  additions  to  the  main 
building  with  special  ventilators,  prevents  the  excessive 
contamination  of  the  tank-house  atmosphere  due  to  the 
fumes  here  given  off.  The  solution  is  maintained  at  a  mean 
temperature  of  120°  F.  by  steam  coils  in  the  wells.  On 
those  circulations  which  include  stripping  tanks  the  solu- 
tion is  cleansed  of  tallow  by  being  forced  under  an  inverted 
dam.  The  tallow  is  removed  from  time  to  time  at  the 
entrance  side  of  the  dam  where  it  collects.  A  circulation 
may  use  the  same  solution  a  number  of  months  before  it 
becomes  sufficiently  foul  to  give  any  trouble;  when  this 
finally  occurs  a  portion  is  run  off  into  a  storage  well  in  the 
cellar  and  replaced  by  fresh  solution.  When  a  sufficient 
quantity  of  foul  solution  has  accumulated  in  this  well  it  is 
run  over  to  the  sulphate  building;  its  subsequent  treat- 
ment is  described  later  in  this  article.  The  following  par- 
tial analyses  of  a  working  solution  and  the  copper  deposited 
from  the  corresponding  bath  are  taken  from  a  regular  assay 
report  of  recent  date: 


Cu. 

% 

As. 
% 

Sb. 

% 

Ag. 
Oz.  per 
Ton. 

Free 

Hfv 

CuSO4 

sH%a 

Sp. 
Gr. 

Mean 
Temp. 

Electrolyte 

4-   25 

I    1  60  1 

O    O2QS 

Q.  12 

l6.7Q 

1  ,22O 

II7°F. 

Cathode.  .  .  . 

99-94 

0.0013 

0.0015 

0.30 

Solutions  more  impure  than  this  are  constantly  in  use. 

When  slimes  are  to  be  removed,  the  tanks  in  question 
are  cut  out  of  service,  the  circulation  being  stopped  by  clos- 
ing the  valves  on  the  individual  supply  pipes  at  the  crest 
of  the  cascade,  and  the  current  being  shut  off  by  short  cir- 
cuiting. The  traveling  crane  then  removes  the  anodes, 


DESCRIPTION  AND  VIEWS  OF  REFINING  WORKS.  73 

a  tankful  at  a  time,  and  similarly  the  cathodes.  The  solu- 
tion in  the  lowest  pair  of  tanks  is  then  emptied  into  the 
launder  through  a  steam  siphon.  The  plug  in  the  bottom 
of  the  tanks  being  pulled  out,  the  slimes  are  sluiced  out  with 
the  residual  few  inches  of  solution  into  the  slime  barrels  in 
the  cellar  below.  The  plug  is  replaced  and  the  solution  in 
the  next  pair  of  tanks  siphoned  into  the  pair  just  cleaned 
and  the  new  electrodes  placed  in  position  by  the  crane, 
and  so  on.  The  circulation  is  stopped  in  10  tanks  at  a  time 
while  cleaning,  the  current,  however,  being  shut  off  from 
but  four  at  a  time.  The  slime  buggies  are  pushed  through 
the  tunnel  into  the  basement  of  the  silver  building,  and 
their  treatment  will  be  described  further  along  in  this 
article. 

Furnace  Buildings. — There  are  three  furnace  buildings 
shown  on  the  ground  plan  (Fig.  16)  at  J,  N,  and  O.  The 
first  is  about  80X600  ft.  and  contains  four  5o-ton  anode 
furnaces  and  five  refining  furnaces  of  the  same  capacity. 
The  second  building  is  80  X  200  ft.  and  contains  four 
25-ton  refining  furnaces.  The  third  building  is  the  blast- 
furnace building,  which  will  be  considered  under  a  separate 
heading.  These  buildings  have  steel  skeletons,  corru- 
gated-iron sides  and  roof,  and  checkered  cast-iron  floor- 
plates.  The  nine  5o-ton  furnaces  are  equipped  with  mechan- 
ical conveyors  for  the  rapid  casting  of  anodes  in  the  case 
of  four  furnaces  and  wire  bars  in  the  case  of  the  others. 
One  2  5 -ton  furnace  is  furnished  with  a  special  conveyor  for 
casting  cakes.  The  three  others  are  used  for  making  ingots 
and  molds  by  hand  ladling  and  one  of  them  has  a  pit  for 
making  shot  copper.  A  section  of  the  large  furnace  build- 
ing is  shown  in  Fig.  25  and  plan  and  sections  of  a  5o-ton 
furnace  are  shown  in  Fig.  26.  The  charging  side  of  the 
building  being  next  to  the  tank-house  allows  a  ready  hand- 
ling of  cathodes  to  the  refining  furnaces.  The  tracks  of 
the  industrial  railroad  run  the  length  of  the  building  on  both 


74 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


sides.  On  the  pouring  side  there  is  a  traveling  crane  and 
a  number  of  small  jib  cranes.  At  one  end  of  the  building 
is  a  ladle-drying  furnace  where  the  clay  linings  of  ladles  are 
quickly  and  cheaply  baked. 

The  refining  process  presents  nothing  worthy  of  special 
note,  the  customary  rabbling  and  poling  being  followed. 


.  FIG.  25. — Section  through  Furnace  Building. 

The  blister  or  anode  furnaces  pour  a  daily  charge  of  up 
to  150,000  Ib.  each,  which  has  been  mixed  to  produce 
anodes  containing  from  100  to  120  oz.  of  silver  per  ton. 
The  daily  output  of  the  wire-bar  furnaces  reaches  120,000 
Ib.  each. 

The  mechanical  conveyor  of  one  of  the  wire-bar  furnaces 
is  shown  in  the  photograph  (Fig.  27).  The  molten  copper 
is  received  in  a  ladle  placed  directly  below  the  tap-hole 
launder,  and  is  thence  delivered  to  molds  brought  succes- 
sively into  position  by  a  table  conveyor.  The  ladle  is  of 
sufficient  size  to  hold  the  copper  which  flows  from  the  spout 


DESCRIPTION  AND    VIEWS   OF  REFINING    WORKS. 


75 


while  the  conveyor  is  in  motion.  The  stream  from  the 
furnace  is  governed  by  bits  of  wood  thrust  into  the  spout. 
The  ladle,  which  is  of  iron,  clay-lined,  is  raised  and  lowered 
by  a  hydraulic  piston  controlled  by  the  ladler.  The  cop- 
per in  the  ladle  is  protected  from  oxidizing  influences  by 
a  layer  of  charcoal.  The  conveyor  consists  essentially  of 
a  series  of  copper  molds  carried  by  an  endless  chain  of  link 


LONGITUDINAL  SECTION 


CROSS  SECTION  OF 
FIRE  PLACE 


TT    i  I    I   I 

PLAN 


FIG.  26. — Details  of  the  Fifty-ton  Copper-refining  Furnace. 

work.     The  system  is  moved  by  a  lo-H.P.  series  railway, 
motor  governed  by  the  customary  controller  and  geared 
to  the  driving  head  at  one  end  of  the  chain.     The  molds 
proper  are  mounted  on  four-wheel  carriages,  the  two  pairs 
of  wheels  of  which  travel  on  pairs  of  rails  of  different  gauge, 
so  that  a  mold  depends  for  its  inclination  from  the  horizontal  ~ 
upon  the  relative  positions  of  the  two  sets  of  rails  at  the 
point  of  travel  in  question.     The  longitudinal  axis  of  the 
mold  is  in  line  with  the  issuing  stream  of  copper,  but  the  / 
line  of  passage  of  the  mold,  when  the  conveyor  is  in  motion, 
is  at  right  angles  to  this  stream..    The  first  condition  per- 


76  MODERN  ELECTROLYTIC  COPPER  REFINING. 

mits  the  mold  to  be  rapidly  filled  without  splashing  or 
causing  any  pinching  from  unequal  heating,  while  the 
second  condition  prevents  the  " heeling  up"  of  the  still 
liquid  metal  at  the  end  of  the  mold,  which  would  result 
from  the  long  waves  produced,  were  the  motion  in  the 
other  direction.  The  molds  now  filled  are  lowered  hori- 
zontally, by  means  of  the  double  rails,  into  water  boshes, 
where  they  remain  long  enough  to  cool  without  becoming 
totally  chilled.  As  the  entire  mold  with  casting  in  place 
is  submerged,  unequal  contraction  and  consequent  trouble 
in  delivering  true  castings  is  avoided.  As  the  conveyor 
proceeds,  the  link  work  carries  the  mold  and  contained 
casting  out  of  the  water  and  suspends  them  vertically  for 
a  moment  to  drain  off  the  surplus  water;  it  then  moves 
over  the  driving  head  and  dumps  the  finished  wire  bar  on 
guides  which  lead  to  a  small  truck.  (In  the  photograph 
the  steam  may  be  seen  rising  from  the  water  bosh  and  the 
mold  which  is  draining  is  clearly  shown.  As  the  picture 
was  a  time  exposure  it  was  necessary  to  stop  the  flow  of 
metal  from  the  launder.)  The  mold  under  consideration 
now  passes  beneath  on  the  return  trip,  where  it  is  daubed 
with  bone-ash  wash  by  an  attendant  and  thoroughly  dried 
by  a  current  of  hot  air.  The  attendant  in  the  pit  marks 
on  the  inside  of  the  mold  the  exact  height  to  which  it  should 
be  filled  to  give  a  bar  of  the  standard  dimensions. 

The  use  of  this  casting  device  not  only  reduces  the  skilled 
labor  to  a  furnaceman  and  his  helper,  but  allows  charges 
of  120,000  Ib.  to  be  poured  in  from  four  and  a  half  to  six 
hours,  depending  on  the  size  of  the  bar  made,  frequently 
without  a  single  bad  casting. 

The  conveyors  for  the  anode  furnaces  differ  in  detail  but 
not  in  principle.  The  bosh  is  omitted  as  the  appearance 
of  the  casting  is  no  longer  an  object  and  the  casting  itself 
is  so  shaped  that  it  cools  sufficiently  for  rough  handling 
without  the  use  of  water.  The  final  cooling  is  usually 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  77 

accelerated  by  a  thorough  wetting  down  with  a  hose  after 
the  anodes  are  stacked  up.  The  anode  is  prevented  from 
sticking  in  the  mold  by  a  pin,  which  automatically  forces 
it  out  from  below,  and  is  delivered  on  a  pair  of  arms  very 
much  as  a  sheet  of  paper  is  delivered  from  a  jobber's  print- 
ing-press. A  pneumatic  hoist  now  takes  it  with  a  pair  of 
tongs  and  places  it  on  a  car  specially  designed  for  handling 
hot  material.  Each  of  these  anode  conveyors  delivers 
without  special  effort  a  charge  reaching  sometimes .  over 
150,000  Ib.  in  three  hours.  This  figure  is  from  actual  work- 
ing results  and  not  a  special  estimate.  In  the  cake-copper 
conveyor  a  reciprocating  train  is  substituted  for  the  endless 
chain  and  unloading  cranes  are  provided  at  each  end,  the 
cakes  being  taken  off  at  one  end  of  the  train  while  the  molds 
at  the  other  end  are  being  filled  from  the  ladle  situated 
midway  between  the  cranes.  The  unloading  device  con- 
sists of  two  pneumatic  hoists,  one  small  and  one  large. 
The  small  one  removes  the  frame  in  which  the  cake  is  cast 
and  the  large  one  then  lifts  the  cake  and  carries  it  to  a  car 
placed  conveniently  on  the  industrial  railroad. 

The  shot-copper  well  presents  no  particularly  novel 
features.  There  is  a  launder  direct  from  the  furnace,  and 
the  issuing  stream  of  metal  is  met  by  an  air-blast  and  a 
thin  sheet  of  water  which  break  it  up  into  the  desired  form ; 
the  shot  falls  to  the  bottom  of  the  well  and  is  caught  in  an 
iron  basket  which  when  full  is  lifted  out  by  a  crane  and 
the  shot  dumped  into  a  suitable  car.  Over  8000  Ib.  are 
handled  at  a  time  in  the  basket. 

Silver  Building. — In  this  building,  which  is  of  substan- 
tial brick  construction,  the  slimes  are  separated  into  fine 
silver  and  gold  by  the  sulphuric  acid  process.  The  slimes 
are  trucked  in  barrels  through  the  tunnel  from  the  base- 
ment of  the  tank-house  on  to  a  hydraulic  lift  which  carries 
them  to  the  top  of  one  end  of  the  silver  building.  They 
are  dumped  on  an  8-mesh  screen,  the  coarse  copper  removed, 


78  MODERN  ELECTROLYTIC  COPPER  REFINING. 

and  the  slimes  washed  through  to  a  6o-mesh  screen.  The 
scrap  copper  from  these  screens  is  returned  to  the  anode 
furnaces.  The  slimes  are  received  in  three  settlers,  which 
in  turn  deliver  them  to  six  agitators.  The  water  from  the 
settlers  is  siphoned  to  a  settling  system  outside  of  the  build- 
ing. In  the  agitators,  sulphuric  acid  is  added,  compressed 
air  introduced,  steam  in  the  heating  coils  turned  on,  and 
the  slimes  and  solution  kept  thoroughly  agitated  by  pad- 
dles. After  settling,  the  solution  being  run  to  the  outside 
settling  system  and  finally  to  the  sulphate  building  to  be 
worked  into  copper  sulphate,  the  slimes  now  free  from 
copper  are  sluiced  into  six  drying  tanks.  Up  to  this  point 
the  slimes  have  been  carried  from  tank  to  tank  by  gravity. 
When  thoroughly  dried  by  steam  coils  they  are  sampled, 
weighed,  and  taken  to  the  furnace-room  adjoining.  They 
now  contain  from  40%  to  50%  silver.  The  slimes  are  now 
charged  in  water- jacketed  cupel  furnaces,  of  which  there 
are  two,  each  accommodating  a  charge  of  from  2000  to  3000 
Ibs.  The  resulting  silver  slabs  are  taken  to  parting  kettles 
while  the  slag  is  melted  with  lead  in  a  small  reverberatory. 
The  liquor  from  the  parting  kettle  is  carefully  siphoned  off, 
and  after  settling  the  entrained  gold,  it  is  run  into  precip- 
itating tanks,  the  cement  silver  from  which  is  dried  in 
special  ovens  and  melted  into  silver  bars  990  fine,  each 
weighing  about  1000  oz.  The  dore  bars  from  the  parting 
kettles  are  re -parted  in  a  third  kettle  and  the  resulting  gold 
sediment  carefully  washed  and  melted  in  a  small  special 
furnace  into  gold  bars  985  to  990  fine,  weighing  about  500 
oz.  each.  All  of  the  furnaces  lead  into  a  long  flue  with  a 
series  of  dust-chambers  terminating  in  an  8o-ft.  brick 
stack.  The  flue-dust  is  charged  with  the  slimes  into  the 
cupel  furnaces.  The  acid  used  is  handled  here,  as  else- 
where in  the  works,  by  compressed  air,  iron  storage  tanks 
being  provided,  into  which  the  contents  of  the  acid -tank 
cars  are  siphoned.  Compressed  air  admitted  to  these 


DESCRIPTION  AND  VIEWS  OF  REFINING  WORKS.  79 

tanks  forces  the  acid  through  a  piping  system  to  wherever 
required. 

Sulphate  Building. — The  building  is  of  brick  and  is  de- 
voted entirely  to  making  copper  sulphate.  The  foul  solution 
is  pumped  from  the  storage  well  in  the  tank-house  cellar, 
by  means  of  steam  injectors,  to  this  building,  where  it  is 
allowed  to  trickle  through  a  series  of  oxidizing  tanks  con- 
taining shot  copper,  with  a  corresponding  series  of  settling 
tanks  interposed.  Thus  the  excess  of  free  acid  is  neutralized 
and  the  sediment  thrown  down  and  separated.  The  solution 
is  then  boiled  to  38°  or  40°  B.  and  run  into  crystallizing 
tanks.  There  are  four  oxidizing,  five  settling,  three  boiling 
and  30  crystallizing  tanks.  The  crystallizing  tanks  are  built 
over  a  cellar  similar  to  that  of  the  tank-house,  which  allows 
a,  thorough  inspection  for  leaks.  At  the  end  of  the  building 
is  a  washing  pan  and  a  revolving  conical  screen  for  sizing. 
The  shaft  carrying  the  screen  is  hollow  and  affords  a  means 
of  introducing  jets  of  hot  air  to  dry  the  crystals  while  they 
are  being  screened.  When  the  mother  liquor,  which  is  worked 
over  several  times,  becomes  so  foul  that  the  crystals  are 
poor,  it  is  sent  to  a  series  of  iron  precipitating  tanks  outside 
the  building  and  the  copper  content  recovered  in  cement 
form. 

Blast-furnace  Building. — The  blast-furnace  building,  like 
the  other  furnace  buildings,  is  built  with  a  steel  skeleton 
carrying  corrugated-iron  sides  and  roof.  The  main  floor  is 
at  the  ground  level  and  is  covered  with  checkered  cast- 
iron  floor  plates.  The  charging  floor  above  is  of  heavy 
planking  carried  by  steel  floor  beams  and  is  covered  with 
plate  iron  around  the  charging  door.  The  equipment  con- 
sists of  a  33  X  66-in.  Fraser  &  Chalmers  water-jacket  furnace, 
with  the  usual  dust-chambers  terminating  in  an  iron  stack, 
a  30-H.P.  shunt  motor,  a  No.  6 A  Green  rotary  blower,  a 
4Xio-in.  Blake  crusher,  a  bucket  elevator,  and  a  hydraulic 
lift.  The  material  after  crushing  is  carried  by  the  bucket 


8o 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


elevator  to  a  series  of  bins  on  the  charging  floor,  near  which 
are  the  usual  charging  scales.  The  hydraulic  lift  outside 
the  building  allows  material  to  be  trucked,  directly  when 
desired.  The  slag  is  dumped  on  lowlands  near  the  building, 
and  the  pigs  of  copper  are  loaded  on  cars  of  the  industrial 
railroad  to  be  taken  to  the  anode  furnaces.  The  flue-dust, 
is  charged  back  daily  without  briquetting.  The  furnace  is 
used  solely  for  the  reduction  of  the  oxide  slag  from  the 
reverberatories.  Oyster  shells  from  the  adjacent  beds  and 
burnt  pyrites  from  chemical  works  in  the  vicinity  afford 
advantageous  sources  of  the  lime  and  iron  needed  as  flux. 

Product. — The  output  of  the  works  in  refined  copper  is 
cast  into  wire  bars,  ingots,  cakes,  and  slabs  of  various  stand- 
ard sizes  as  stated  below.  The  quality  of  the  copper  is 
shown  by  the  following  average  results,  which  were  obtained 
from  a  number  of  lots  recently  tested  and  analyzed: 


Physical  Properties. 

Composition. 

Percentage  of  Conduc- 
tivity.   Matthiessen's 
St'd.     Annealed. 

Tensile  Strength. 
Hard-drawn  to  No.  1  2 
B.&S. 

Twists  in 
6  inches. 
Hard-drawn. 

Cu. 

% 

As. 

% 

Sb. 
% 

IOO.  1 

66,600 

43 

99-94 

O.OO2O 

0.0033 

This  checks  closely  the  figure  obtained  (100%)  for  the 
average  conductivity  of  all  lots  produced  during  a  recent 
month,  the  determination  of  the  conductivity  of  each  lot 
being  part  of  the  daily  work  of  the  physical  laboratory. 


2.  Guggenheim  Refinery  (Perth  Amboy  Plant). 

The  Guggenheim  electrolytic  works,  now  the  Perth 
Amboy  Plant  of  the  American  Smelting  and  Refining  Com- 
pany, were  built  in  1895  at  Perth  Amboy,  N.  J.,  for  refining 
about  10,000  tons  of  argentiferous  copper  annually.  These 
works  were  afterwards  considerably  increased  in  capacity 
and  were  recently  replaced  by  a  well-equipped  larger  refinery 


- 


00 

I 
1 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS. 


Si 


capable  of  turning  out  between  100  and  150  tons  of  elec- 
trolytic copper  daily,  or  at  least  36,000  tons  annually, 
while  the  old  refining  plant,  shown  in  Fig.  30,  has  been  placed 
out  of  commission. 


SIDE  VIEW 


TOP  VIEW 


tt- 

\ 7    CROSS 
\ /  SECTION 

4t- 


FIG.  28. — Shape  of  Wire  Bar  with  Pointed  Ends. 
WIRE  BARS,  POINTED  ENDS.     (Fio.  28.) 


Weight. 


Dimensions  in  Inches. 


Pounds. 

Length. 

Upper  Width  ,WV 

Lower  Width,  W2. 

Depth.  D. 

77 

34* 

3t 

3 

3 

100 

35 

V 

3 

3iV 

135 

.  38 

3; 

3f 

155 

39 

3 

3f 

3i 

175 

53 

3: 

3rV 

3i 

200 

49i 

3 

3i 

3i 

225 

48 

4 

3l 

4 

275 

54 

41 

3l 

41 

300 

51 

4' 

4i 

41 

420 

84 

4 

3| 

41 

575 

88 

4 

4i 

Most  of  the  material  to  be  treated  is  received  at  the 
works  in  the  shape  of  either  pigs  of  blister  copper  or  anodes. 
The  very  rich  gold  and  silver  bearing  blister  copper  from 
Aguas  Calientes,  Mexico,  is  melted  down  with  low-grade 
copper  bullion  in  reverberatory  furnaces  and  partially 
refined  before  it  is  cast  into  anodes  for  the  electrolytic 
treatment. 

The  new  plant  contains  816  depositing  tanks  and  three 
520  kw.  generators,  as  against  360  tanks  in  the  old  plant 
and  two  180  kw.  generators.  Before  considering  the  new 
refinery,  I  will  briefly  describe  the  old  refinery,  with  its 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


SIDE  VIEW 


TOP  VIEW 


FIG.  29. — Shape  of  Wire  Bar  with  Rounded  Ends. 
WIRE  BARS,  BLUNT  ENDS.     (FiG.  29.) 


CROSS" 
SECTION 


Weight. 


Dimensions  in  Inches. 


Pounds. 

Length. 

Upper  Width,  W). 

Lower  Width,  W2. 

Depth,  D. 

135 

37} 

3f 

Sir 

3i 

175 
212 

4<> 

-1  5 

& 

360 

6zi 

44 

4 

4* 

SQUARE  CAKES. 
Dimensions  in  Inches  and  Corresponding  Weights  in  Pounds. 


Th'kness. 
Inches. 

I* 

2 

a* 

3 

3^ 

4 

5 

6 

Size, 
Inches. 

14X17 
18X18 

Pounds. 
Ill 

Pounds. 
I48 
2OI 

Pounds. 
I84 
2SI 

Pounds. 
221 
^OI 

Pounds. 
258 

^S2 

Pounds. 
295 
4O2 

Pounds. 

Pounds. 

2OX  2O 

254 

317 

381 

44  S 

508 

615 

24.X  24. 

466 

5^6 

62=; 

714. 

RQ-} 

26X  26 

K-II 

64.4. 

752 

860 

I  O7  ^ 

28X  28 

72Q 

851 

Q72 

I   215 

I  4.t;8 

•^2X^2 

077 

I     I  -50 

I     -7QI 

I  628 

I  Q^^ 

•^7X^7 

i  4.85 

I    608 

2  122 

2   54.6 

18X^8 

I    6O7 

i  8^6 

2  2Q5 

2755 

40X40 

1,780 

2  O^S 

2   54.4. 

•7    O52 

45X45 

2.2S4 

2,S?6 

3  2OO 

3    864. 

SLABS. 
Dimensions  in  Inches  and  Corresponding  Weights  in  Pounds. 


Thickness. 
Inches. 

i* 

2 

a* 

3 

3* 

4 

5 

Size, 

Inches. 

Pounds. 

Pounds. 

Pounds. 

Pounds. 

Pounds. 

Pounds. 

Pounds. 

30  X8 

114 

152 

190 

228  . 

296 

304 

380 

10  X25 

118 

156 

I97 

237 

277 

316 

395 

12  X22 

125 

1  66 

208 

249 

29I 

332 

415 

24*  X  8 

93 

124 

155 

1  86 

217 

248 

310 

48  X5i 

126 

168 

210 

252 

294 

336 

420 

48  X4* 

102 

136 

170 

204 

238 

272 

340 

DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  83 

3o-ton  tank-house  arid  equipment,  because  of  some  of  its 
interesting  features. 

A.  The  Old  Refining  Plant. — The  boiler-house  contained 
five  Babcock  &  Wilcox  boilers,  rated  at  125  H.P.  each,  and 
generating  steam  at  150  Ibs.  pressure,  part  of  which  was 
utilized  for  power  purposes  in  the  lead  refinery. 

Two  Porter-Allen  triple-expansion  condensing  engines, 
running  at  250  r.  p.  m.,  drove  two  i8o-kw.  General  Electric 
generators,  one  of  which  is  shown  in  Fig.  31.  These  genera- 
tors were  of  the  8-pole  multipolar  type,  shunt  wound,  with 
smooth  core  armatures  of  the  ring  type,  and  delivered  1500 
amperes  at  120  volts. 

Good  satisfaction  was  given  by  woven-wire  brushes,  of 
which  there  were  three  to  each  brush-holder,  or  twenty- 
four  in  all,  the  cross-section  of  each  brush  being  TVXiif 
in.  The  switchboard  is  shown  in  Fig.  31. 

The  cathode  or  stripping  tank  system  was  supplied  by 
a  i2-kw.  General  Electric  generator,  shown  in  Fig.  32, 
driven  by  a  standard  25-H.P.  Westinghouse  engine.  It  was 
a  4-pole  machine,  with  its  field  separately  excited  from  a 
1 10- volt  power  circuit,  and  delivered  1,000  amperes  at  12 
volts.  The  commutator  was  24  inches  in  length,  14  inches 
in  diameter,  and  contained  40  segments,  each  iyV  in.  wide. 
The  brushes,  64  in  number,  were  of  carbon,  1.25  in.  in 
cross-section,  and  contained  a  copper-wire  core. 

In  the  power-house  there  were  also  two  4-pole  4o-kw. 
power  generators  and  a  40-kw.  no- volt  incandescent 
lighting  generator. 

The  tank-house  contained  two  groups  of  tanks:  i,  those 
for  refining  proper,  called  the  commercial  depositing  tanks, 
and  2,  those  for  making  starting  sheets  or  cathodes.  - 

In  the  cathode  tanks  rolled  copper  plates  o.i  in.  thick 
were  employed  to  receive  the  cathode  deposit,  which  was 
permitted  to  become  0.04  in.  thick,  both  sides  of  the  rolled 
copper  being  thus  plated.  In  former  practice  wood  strips 


84  MODERN  ELECTROLYTIC  COPPER  REFINING. 

formed  a  frame  about  three  sides  of  the  plates,  but  now 
grooves  filled  with  insulating  material  serve  the  same  pur- 
pose. The  two  surfaces  of  the  plates  were  oiled  and  covered 
with  graphite  in  order  to  prevent  the  cathode  deposits  from 
sticking,  and  the  plates  were  placed  in  tanks  between 
ordinary  anodes.  After  the  necessary  thickness  of  copper 
had  been  deposited  the  sheets  were  stripped  from  the  plates 
and  were  then  ready  for  use  as  cathodes  in  the  commercial 
tanks.  There  were  thirty  cathode  tanks,  each  8  ft.  6  in. 
long,  3  ft.  deep,  and  2  ft.  6  in.  wide,  supplied  with  current 
by  conducting  bars  1.25  in.  square,  placed  alongside  of  each 
tank. 

A  general  view  of  the  tanks  for  the  commercial  depo- 
sition of  copper  is  shown  in  Fig.  30.  They  were  arranged 
in  pairs,  forming  so-called  double  tanks,  as  shown  in  Fig. 
33,  and  grouped  in  terraces,  with  a  difference  in  level  of 
about  two  inches  between  each  row.  The  commercial  tanks 
were  constructed  of  2 -in.  pitch-pine  coated  with  P.  &  B. 
paint,  each  being  9  ft.  10  in.  long,  3  ft.  deep,  and  2  ft.  6  in. 
wide.  The  electrolyte  as  prepared  for  the  bath  had  in  solu- 
tion, by  weight,  16%  bluestone  and  5%  free  sulphuric  acid. 

Each  tank  contained  22  anodes  and  23  cathodes.  The 
anodes  were  cast  2  ft.  6  in.  long,  2  ft.  wide,  and  1.25  in. 
thick,  and  had  the  form  shown  in  Fig.  34. 

All  of  the  360  tanks  were  placed  in  series,  and  the  plates 
of  each  tank  in  multiple.  A  copper  conducting  bar  1.75 
in.  square,  afterwards  replaced  by  a  bar  1.5  X  3  in.  in  section, 
was  supported  along  the  outer  edge  of  each  tank,  and  a 
copper  strip  i  in.  wide  and  0.25  in.  thick  was  placed  on  top 
of  the  double  partition  wall  between  each  pair  of  tanks. 
The  tops  of  the  cathodes  were  bent  over  and  hung  from 
J-in.  square  copper  cross-bars.  Fig.  35  illustrates  how  the 
electric  current  was  distributed.  It  will  be  seen  that  the 
tanks  of  each  pair  are  in  series  the  same  as  the  adjacent 
pairs  of  tanks. 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  85 

The  anode  and  cathode  plates  were  separated  by  about 
1.25  in.  The  current  density  was  about  ten  amperes  per 
square  foot  (counting  both  sides  of  the  anode  plate),  and 
it  required  about  twenty-four  days  of  twenty-four  hours 


each  to  electrolytically  transfer  tne  copper  of  the  275-lb. 
anode  to  the  cathode  plate.  The  voltage,  of  course,  depended 
only  upon  the  ohmic  resistance  of  the  electrolyte,  conduc- 
tors, and  plates.  It  averaged  between  0.3  and  0.4  volt  per 


86  MODERN  ELECTROLYTIC  COPPER  REFINING. 

tank.  With  356  tanks  (four  tanks  were  always  out  of  cir- 
cuit, having  "  slime"  removed  or  being  repaired)  the  volt- 
meter at  the  switchboard  usually  registered  from  117  to  120 
volts,  with  a  current  of  1500  amperes  in  use. 

The  deposited  plates  of  pure  copper  were  either  sold  as 
commercial  cathodes  or  they  were  melted  in  reverberatories 
and  cast  into  wire  bars,  plates,  or  ingots. 

In  the  above-described  refinery  the  copper  treated  was 
unusually  rich  in  precious  metals,  and  frequently  carried  as 
much  as  300  to  600  ounces  of  silver  and  3  to  4  ounces  of  gold 
to  the  ton  of  copper.  The  rich  slimes  accumulating  in  the 
bottom  of  the  tanks  were  carefully  gathered  and  screened 
from  anode  scrap  through  a  perforated  sheet  copper  screen, 
which  was  suspended  in  a  tank  in  which  the  slimes  were 
"  boiled,"  or  stirred  up  with  acid  so  as  to  expose  them  to  air 
as  much  as  possible.  The  boiling  tank  was  a  lead-lined  vat 
filled  with  hot  dilute  sulphuric  acid  (i  of  acid  to  4  of  water) 
to  a  height  reaching  a  little  above  the  bottom  of  the  screen, 
and  provided  with  a  perforated  lead  coil  communicating 
with  a  Korting  injector.  The  injector  supplied  both  hot 
air  and  steam  to  oxidize  and  dissolve  the  impurities  in  the 
slimes  and  thus  to  concentrate  the  silver  and  gold  during 
the  boiling. 

The  slimes  constituted  at  least  4%  of  the  total  weight 
of  the  anode  copper  refined,  and  after  ^screening  averaged 
15%  to  30%  of  metallic  copper,  45%  to  50%  silver,  0.5% 
to  i%  gold,  and  from  20%  to  35%  of  impurities,  such  as. 
arsenic,  antimony,  tellurium,  bismuth,  and  lead,  chiefly  in 
a  more  or  less  oxidized  condition.  Although  the  boiling  was 
not  continued  longer  than  eighL  or  nine  hours,  the  greater 
parts  of  the  arsenic,  antimony,  and  other  impurities  were 
dissolved  and  were  then  removed  by  siphoning  off  the 
solution  and  wash  water  from  the  silver  slimes.  The  latter 
were  then  dried  on  iron  pans  in  a  hot-air  chamber  and  sent 
to  the  lead  refinery. 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  87 

About  forty  laborers,  paid  approximately  $1.10  per  day, 
were  employed  in  the  copper  refinery.  A  comparatively 
large  number  of  men  were  required  because  of  the  need  of 
washing  the  anodes.  This  arose  from  the  fact  that  the 
anodes  ran  unusually  high  in  silver,  and  that  they  had  to  be 
removed  from  the  tanks  from  time  to  time,  and  the  adhering 
film  of  silver  and  other  impurities  scrubbed  off  in  order  to 
prevent  polarization  of  the  anodes  and  a  reduction  of  their 
effective  area. 

The  refinery  occupied  a  floor  space  of  about  200  feet 
square.  Under  a  single  roof  of  several  bays  it  covered  the 
engine  and  dynamo  plant,  the  cathode  and  commercial 
tank  system,  and  the  crystallizing  plant  for  the  recovery 
of  bluestone. 

The  cost  of  the  above  30-ton  refinery  was  approximately 
as  follows: 

Building  (walls,  roof,  and  trusses) $50,000 

Dynamos  and  fixtures 16,000 

Two   Porter-Allen    engines   and  one  small 

Westinghouse  engine •. 11,000 

Air  compressor  and  pumps 2,000 

Lead  for  lining  tanks 12,000 

Copper  conductors 11,000 

Lead  burning 2,500 

Tanks   (woodwork) 10,000 

Lumber  for  floors,  etc 2,500 

Brick  piers  for  tanks 3,500 

Brick  paving 1,000 

Trolleys ' 2,000 

Boiler  plant  (about  500  H.P.) 15,000 

$138,500 

The  above  sum  does  not  include  cost  of  pipes  for  steam 
heating,  nor  of  the  tracks  for  transportation  of  material. 


88  MODERN  ELECTROLYTIC  COPPER  REFINING. 

B.  The  New  Copper -Refining  Plant. — The  new  tank- 
house  of  the  Perth  Amboy  plant  was  erected  during 
1901  and  1902.  From  100  to  150  tons  of  electrolytic 
copper  can  be  refined  in  it  per  diem,  while  the  old 
tank-house  could  not  treat  over  40  or  50  tons  daily. 
The  refinery  is  at  present  running  at  about  two-thirds  of 
its  full  capacity,  the  remaining  one-third  being  held  in 
reserve.  This  will  explain  the  surplus  of  generator  power 
as  compared  with  the  actual  daily  output.  The  plant 
now  comprises  three  520-kw.  generators  and  816  depositing 
tanks,  and  produces  about  100  tons  of  electrolytic  copper 
daily. 

The  new  refinery  is  said  to  embody  an  arrangement, 
patented  and  described  by  Mr.  A.  L.  Walker,  substantially 
as  follows:  The  tanks  are  arranged  with  their  proximate 
walls  parallel  and  close  together,  and  are  supplied  with 
current  by  leading-in  and  leading-out  mains  extending  to 
the  end  tanks  of  a  given  series,  these  mains  being  of  large 
and  sufficient  cross-section  to  carry  the  entire  current  sup- 
plied to  all  the  tanks.  Distributing  bars  of  small  cross- 
sectional  area  are  supported  between  adjacent  tanks,  and 
the  supporting  projections  of  the  anodes  and  of  the  cathodes 
in  adjacent  tanks  rest  freely  on  the  same  distributing  bars, 
whereby  electrical  connection  between  anodes  and  cathodes 
of  adjacent  tanks  is  established  through  connections  indi- 
vidually of  small  and  insufficient  area  to  carry  the  total 
current,  but  collectively  of  an  area  sufficient  to  carry  said 
current.  The  supporting  projections  at  one  side  of  the  anodes 
of  the  first  tank  and  of  the  cathodes  of  the  last  tank  rest 
freely  on  the  leading-in  and  leading-out  mains  respectively. 
With  this  arrangement  heavy  conducting  bars  are  entirely 
done  away  with  between  tanks,  and  the  current  is  carried 
from  tank  to  tank  of  the  series  by  means  of  copper  bars 
having,  according  to  Walker,  only  5%  of  the  area  of  the 
large  conductors,  which  are  usually  5  sq.  in.  in  cross-sec- 


.1   [      -v*^ 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  89 

• 

tional  area,  if  a  4ooo-ampere  current  is  used.  Thus  the 
Caving  in  copper  by  this  arrangement,  in  carrying  the  cur- 
3nt  through  the  series  of  tanks  and  including  the  terminal 
conducting  bars,  is  claimed  by  Walker  to  be  at  least  83% 
of  the  best  former  practice. 

In  casting  anodes,  wire  bars,  and  ingots  in  the  above 
refinery,  four  Walker  casting  machines  of  very  large  capac- 
ity, as  shown  in  Figs.  36  and  37,  are  employed,  and  have 
given  eminent  satisfaction. 

Anodes  provided  with  a  long  and  a  short  lug,  as  first 
used  at  the  Balbach  Refinery,  are  now  employed  at  the 
Perth  Amboy  plant,  instead  of  anodes  of  the  shape  illus- 
trated in  Fig.  34.  In  Walker's  arrangement  the  lugs  of  the 
anodes  in  those  depositing  tanks  not  connected  with  the 
leading-in  mains,  which  receive  the  current,  rest  simply  on 
the  knife  edges  of  small,  triangular  copper  bars,  which  are 
only  about  0.5  sq.  in.  in  sectional  area,  it  is  reported.  It 
might  seem  that  the  ohmic  resistance  at  the  point  of  con- 
tact between  lug  and  this  conducting  bar  would  be  found 
to  be  very  great  when  such  heavy  currents  as  4500  amperes 
are  supplied  to  the  tanks  with  the  usual  voltage.  This  is 
not  the  case,  however,  which  is  rather  remarkable. 

The  silver  slimes  collected  in  the  above  plant  are  first 
treated  with  acid,  and  then  dried  and  sent  to  the  lead  re- 
finery, where  they  are  added  to  charges  in  a  lead  concen- 
trator and  enter  into  the  metal  cupelled  into  dore  bars, 
which  are  subsequently  parted  by  the  Moebius  process 
electrolytically. 

3.  The  Anaconda  Electrolytic  Copper  Refinery. 

The  first  electrolytic  plant  at  Anaconda,  built  during 
1891  I  believe,  was  altered  and  enlarged  to  its  present  design 
and  capacity,  chiefly  under  the  direction  of  Mr.  Hermann 
Thofehrn,  in  the  years  1893-95.  The  present  refinery 


9o 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


covers  about  14,000  sq.  yd.,  and  consists  of  two  sections, 
separated  about  100  ft.  for  security  in  case  of  fire.  The 
boiler-house  and  the  silver  mill  are  located  respectively 


FIG.  38. — Side  View. 


FIG.  39.— End  View. 
Hixon  and  Dyblie  Car  and  Molds  for  Casting  Anodes  Direct  from  Converters. 

200  ft.  and  300  ft.  distant  from  the  tank-houses.     These 
buildings,  as  well  as  the  dynamo-room  which  adjoins  the 


- 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  91 

tank-houses,  are  framed  with  timber,  and  covered  on  their 
sides,'  gable  ends,  and  roof  with  corrugated  iron.  A  large 
number  of  fire  hydrants,  with  hose,  are  distributed  through- 
out the  buildings  and  are  always  kept  in  good  working  order 
by  special  watchmen.  Much  of  the  following  detailed  descrip- 
tion is  taken  from  the  Engineering  and  Mining  Journal  of 
Sept.  19,  1896.  I  will  consider  the  equipment  of  the  boiler- 
house,  engine-  and  dynamo-room,  and  of  the  tank-houses 
i'n  turn,  and  then  describe  the  actual  working  of  the  re- 
finery. 

The  boiler-house  contains  three  sets  of  two  boilers,  each 
of  the  Heine  pattern,  having  altogether  an  evaporating 
capacity  of  62,000  Ib.  of  water  per  hour.  Another  set  of 
two  boilers  of  the  same  capacity  serves  as  a  reserve.  All 
the  boilers  are  connected  by  a  large  iron  flue  which  carries 
the  smoke  and  gases  to  a  feed-water  heater  of  the  Green 
pattern,  from  which  they  are  led  to  a  brick  stack  140  ft. 
high.  The  steam  and  feed- water  lines  are  common  to  all 
the  boilers,  and  the  connections  are  so  made  as  to  permit 
of  connecting  or  disconnecting  any  one  of  the  boilers.  The 
latter  are  supplied  with  American  Co.'s  underfed  stokers, 
which  have  given  great  satisfaction.  The  ashes  are  sluiced 
to  an  elevator  and  finally  dumped  on  the  prairie  adjoining 
the  boiler-house.  From  the  cars  on  a  track  in  front  of 
the  boiler-house,  the  coal  is  dumped  into  large  bins,  from 
which  a  bucket  elevator  takes  it  into  the  supply  bins  sus- 
pended in  front  of  the  boilers.  The  coal  drops  from  these 
bins  to  the  feed-hoppers  and  is  taken  by  the  grates  auto- 
matically and  continuously.  The  feed-water  is  handled 
by  two  large  Knowles  pumps,  each  of  sufficient  capacity 
to  supply  all  of  the  boilers  alone.  The  water  is  taken  from 
the  hot  well  of  the  condenser  and  is  delivered  by  the  pumps 
through  the  Green  heater  to  the  boilers  and  acquires  in 
this  way  a  temperature  of  about  200°  F.  Twelve  men  are 
employed  in  the  boiler-house. 


92  MODERN  ELECTROLYTIC  COPPER  REFINING. 

The  engine-  and  dynamo-room  (see  Fig.  40)  contains, 
a  Corliss  engine  of  about  800  H.P.,  a  Westinghouse  com- 
pound engine  of  400  H.P.,  and  two  triple-expansion  engines 
of  900  H.P.  each.  The  two  last-named  engines  are  directly 
•coupled  to  two  dynamos  each.  This  makes  a  total  of 
.about  3000  H.P.  The  Corliss  engine  runs  the  dynamos 
of  the  old  section  of  the  refinery  at  present  by  means  of 
belting  and  shafting.  The  current  for  the  electrolytic 
work  is  supplied  by  two  220  kw.  Westinghouse  generators, 
belt  driven,  and  five  270  kw.  Westinghouse  generators, 
one  of  which  is  belt  driven,  while  the  other  four  are  directly 
connected  to  the  two  triple-expansion  engines.  This  makes 
altogether  1790  kw.,  corresponding  to  2560  H.P.  Out  of 
this  total,  one  generator  together  with  the  400  H.P.  engine 
are  kept  in  reserve,  being  an  electrical  unit  of  220  kw., 
equivalent  to  315  H.P.  This  reserve  unit  can  be  switched 
over  to  any  one  of  six  circuits  in  case  of  an  accident  or 
repairs  to  any  of  the  six  generators  regularly  running. 
These  generators  are  controlled  from  a  central  switch- 
board, to  which  all  but  two  of  the  conductors  lead. 

Of  the  boiler  output  of  62,200  Ib.  of  water  evaporated 
per  hour,  the  two  triple-expansion  engines,  while  produc- 
ing at  the  normal  rate  1080  kw.  or  1544  H.P.,  consume 
at  the  rate  of  15  Ib.  per  horse-power  per  hour  or  23,160  Ib. 
of  water.  The  double  Corliss  engine,  while  producing 
normally  490  kw.,  equal  to  700  H.P.  or  750  H.P.  when  the 
belting  losses,  etc.,  are  added,  consumes  at  the  rate  of 
30  Ib.  of  water  per  horse-power  or  22,500  Ib.  per  hour. 
Besides  the  generators  for  electrolytic  work  there  are  two 
dynamos  for  light  and  power,  one  being  held  in  reserve. 
These  require  about  50  H.P.,  equal  to  1500  Ib.  of  steam. 
Then  there  is  a  30-H.P.  air-compressor  which  runs  the  acid 
pumps  and  consumes  about  900  Ib.  of  steam.  The  con- 
densers for  the  Corliss  and  for  the  triple-expansion  ma- 
chines take  another  1500  Ib.  of  steam  per  hour.  The 


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DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  93 

machinery  mentioned  in  the  aggregate  consumes  a  total 
of  49,560  Ib.  of  water,  which  added  to  1500  Ib.  required 
for  heating,  makes  51,060  Ib.  of  water  which  must  be 
evaporated  in  the  boilers.  This  is  amply  provided  for, 
as  the  maximum  capacity  of  the  boiler  plant,  excluding 
the  reserve  boilers,  is  62,200  Ib.  of  water.  The  total 
amount  of  power  consumed  corresponds  to  a  maximum 
production  of  150  tons  of  electrolytic  copper  per  24  hours, 
or  to  about  17  J  H.P.  per  ton  of  copper  produced.  This 
includes  the  power  required  for  the  lifting,  the  transport- 
ing, and  handling  of  the  copper,  which  is  done  by  electric 
appliances,  the  manufacture  of  the  cathodes,  the  opera- 
tion of  the  silver  mill,  as  well  as  the  production  of  heat 
and  light.  Labor  being  more  expensive  in  Anaconda  than 
power,  it  is  replaced  wherever  possible  by  machinery. 

The  refinery  proper  (see  Fig.  41)  is  built  in  two  sections, 
each  tank-house  covering  a  ground  space  of  about  6500  sq. 
yd.  and  containing  600  electrolytic  tanks.  The  tanks  are 
2.50  m.  or  about  8  ft.  long,  1.50  m.  or  about  5  ft.  8  in. 
wide,  and  i.oo  m.  or  3  ft.  3  in.  deep.  They  are  built  on  the 
self-insulating  plan,  that  is,  they  are  so  constructed  as  to 
allow  free  access  of  air  to  their  walls  and  bottom.  A  row  of 
tanks  is  formed  simply  by  covering  a  timber  framework  on 
the  inside  with  common  planks,  and  cutting  it  up  into  ten 
compartments  by  nine  double  partitions  of  the  same  material, 
so  as  to  form  a  row  of  ten  tanks.  Each  row  is  set  on  its  own 
foundation,  entirely  separate  from  the  others,  and  from  the 
working  floor.  A  large  air-space  is  left  between  each 
compartment,  so  that  all  parts  of  the  tanks,  the  sides  as 
well  as  the  bottom,  are  easily  accessible.  Every  joint  in 
the  woodwork  of  the  tanks  and  of  the  foundations  is  insu- 
lated by  soaking  with  insulating  material  before  the  tim- 
bers and  planks  are  put  together.  The  lead  lining  of  the 
tanks  is  protected  by  boards  against  injury  from  falling 
anode  scrap.  The  electric  conductors  are  placed  on  the 


94  MODERN  ELECTROLYTIC  COPPER  REFINING. 

sides  of  the  tanks  and  serve  as  supports  for  the  electrodes. 
The  bars  are  bent  in  the  middle,  so  as  to  reach  over  two 
tanks,  being  positive  on  one  and  negative  on  the  other 
tank.  By  means  of  this  bend  in  the  bars  all  screw  con- 
nections are  avoided  between  the  tanks,  and  thus  only 
the  different  rows  require  to  be  connected  in  the  usual 
way.  This  effects  an  important  saving  of  labor  and  power, 
as  it  is  very  difficult  to  maintain  good  joints  for  so  heavy 
a  current  in  an  atmosphere  charged  with  acid  and  steam, 
or  moisture.  To  support  the  electrodes,  flat  iron  bars  are 
laid  across  the  tanks  and  rest  on  the  conductors.  Copper 
hooks  sustain  the  plates  in  the  liquid  and  are  hooked  on 
these  bars.  Ten  rows  make  a  set  of  100  tanks,  and  two 
sets  make  a  system  of  200.  Each  system  fills  a  bay,  and 
each  bay  of  the  tank-houses  is  provided  with  a  complete 
outfit  of  machinery,  tools,  and  appliances,  making  it 
entirely  independent  of  the  other  bays  and  forming  a  com- 
plete unit  by  itself.  As  the  composition  of  the  crude 
copper  changes  in  regard  to  its  impurities  and  as  the  elec- 
trolyte has  to  be  altered  according  to  the  amount  of  such 
impurities,  it  is  absolutely  necessary  to  be  able  to  sepa- 
rate each  system  from  the  others.  There  are  six  systems 
of  like  capacity  of  200  tanks,  each  being  able  to  turn  out 
between  25  and  35  tons  of  electrolytic  copper  per  24  hours 
as  a  maximum.  All  the  tanks  of  each  system  are  elec- 
trically connected  in  series  and  supplied  with  current  pro- 
duced by  one  generator.  Each  row  of  10  tanks  has  its 
individual  supply-tank  for  the  circulation  of  the  liquid. 
The  circulation  is  established  by  having  the  rows  built  on 
an  inclined  plane.  The  liquid  runs  by  gravity  from  one 
tank  to  the  next  until  it  reaches  the  last  one,  from  which 
it  falls  to  the  collecting  tank.  The  latter  conveys  the 
liquid  to  the  acid  pumps,  working  by  air  pressure,  which 
deliver  it  to  the  distributor  and  from  there  to  the  small 
supply-tanks  to  begin  the  same  course  anew. 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  9$ 

The  three  systems  of  the  old  tank-house  are  provided 
with  overhead  trolleys,  one  above  each  double  row,  by 
means  of  which  the  tanks  are  loaded  with  anodes  and  the 
cathodes  are  taken  away.  The  full  copper  charge  of  a 
tank,  weighing  about  four  tons,  is  loaded  up  or  unloaded 
in  one  operation.  In  the  three  systems  of  the  new  tank- 
house  each  bay  has  a  single  electric  crane  spanning  its 
whole  width,  also  designed  to  charge  a  full  tank  load  at 
once.  The  reason  why  the  first  three  systems  were  not 
provided  with  elecric  cranes  is  that  the  old  tank-house  was 
not  suitable  for  their  installation,  and  the  time  given  for 
the  construction  of  the  plant  was  too  short  to  alter  the 
buildings  and  to  await  the  construction  of  the  cranes.  On 
the  working  floor  of  the  bays  runs  an  electric  road  of  2o-in. 
gauge,  by  means  of  which  all  material  is  conveyed  from 
the  full-gauge  railroad  in  the  buildings  to  and  from  the 
tanks.  The  locomotives  were  designed  by  Mr.  Thofehrn 
and  built  by  the  General  Electric  Co.  Underneath  the 
tanks  runs  another  2o-in.  road,  which  is  used  to  convey 
the  silver  slimes  to  the  silver  mill. 

Operation  of  the  Refinery.  The  work  in  the  refinery 
is  carried  out  as  follows:  The  men  take  the  anodes  from 
the  railroad  cars,  transport  them  by  the  tank  load  over 
the  scales,  and  place  them  on  a  rack.  Here  the  support- 
ing bars  and  hooks  are  laid  over  the  anodes  and  the  crane 
then  picks  up  the  charge,  conveys  it  to  the  tank  desired, 
lets  it  down  therein,  and  at  the  same  time  places  all  the 
plates  in  their  proper  position.  In  the  meantime  another 
crew  of  men  has  placed  a  load  of  cathode  sheets  on  a  second 
rack,  hooked  on  to  the  supporting  bars  and  ready  for  use. 
These  are  now  taken  up  by  the  crane  and  brought,  like 
the  anodes,  to  the  exact  place  where  they  belong.  After 
this  the  tank  is  filled  with  solution,  the  electric  current 
started,  and  the  refining  work  begun.  The  circulation  of 
the  solution  and  the  electric  current  are  stopped  only  in 


96  MODERN  ELECTROLYTIC  COPPER  REFINING. 

those  tanks  which  are  being  reloaded  and  then  only  for 
the  time  strictly  required  for  this  operation.  This  time, 
which  includes  unloading,  cleaning,  and  reloading,  bring- 
ing in  of  fresh  material,  its  preparation,  etc.,  hardly  ex- 
ceeds one  hour  for  each  tank.  The  unloading  of  the  tanks 
goes  on  in  about  the  same  manner  as  the  loading,  i.e.,  the 
passage  of  the  electric  current  and  the  circulation  of  the 
solution  are  discontinued,  the  crane  takes  out  the  full 
charge  of  cathode  plates,  and  brings  it  down  to  a  small, 
electrically  driven,  2o-in.  gauge  car,  which  conveys  it  to 
the  railroad  for  shipment.  The  remnants  of  the  anodes 
in  the  tanks  are  then  taken  out,  the  silver  slimes  are  re- 
moved, and  the  tanks  prepared  to  be  loaded  up  again.  A 
current  density  of  10  to  20  amperes  per  square  foot  of 
cathode  surface  is  generally  employed. 

The  crude  material  which  the  refinery  treats  is  blister  cop- 
per, containing  98%  Cu  on  an  average,  and  small  amounts 
of  arsenic,  antimony,  iron,  lead,  tellurium,  selenium,  be- 
sides about  no  oz.  of  silver  and  J  oz.  of  gold  per  ton.  The 
blister  copper  was  formerly,  if  not  at  present,  cast  into 
anodes  direct  from  the  converters,  by  employment  of  the 
car  and  molds  shown  in  Figs.  38  and  39,  which  are  fully 
described  in  U.  S.  patent  No.  539,270  of  May  14,  1895, 
granted  to  H.  Hixon  and  J.  Dyblie. 

The  large  number  of  tanks  and  the  high-cost  price  of 
labor  at  Anaconda  necessitated  a  special  means  of  control- 
ling the  refining  operation.  This  control  was  secured  by  an 
automatic  register,  to  which  all  tanks  were  connected  by 
series  of  five  tanks  each.  A  yoke  carrying  two  brushes 
slides  over  the  different  sections  of  a  commutator-like 
device,  making  one  complete  turn  in  an  hour,  and  these 
brushes  bring  into  contact  the  terminals  of  each  series  of 
five  tanks  to  register  the  volt  meter.  In  this  way  all  the 
tanks  are  controlled  once  an  hour  and  the  readings  regis- 
tered on  paper  automatically.  This  enables  the  man  in 


DESCRIPTION  AND   yiEWS  OF  REFINING   WORKS.  97 

charge  to  see  at  a  glance  the  condition  of  all  the  tanks  in 
the  refinery.  He  can  see  at  once  if  any  trouble  is  in  any 
one  of  the  tanks;  of  what  nature  the  trouble  is;  when  it 
started  and  how  it  developed.  He  is  able,  then,  to  point 
out  to  the  foreman  the  tank  in  question,  and  this  instru- 
ment keeps  on  recording  when  the  man  started  to  correct 
the  trouble,  how  much  time  it  took  him  to  do  it,  and  also 
how  completely  the  work  was  done.  The  register  costs  $500 
and  the  wiring  about  $1000. 

The  Anaconda  Copper  Mining  Co.'s  refinery  in  1896 
turned  out,  it  is  claimed,  between  100  and  120  tons  of 
electrolytic  copper  daily,  and  besides  sent  80  to  100  tons 
of  blister  copper  for  refining  to  Baltimore.  Although  the 
plant  was  designed  to  handle  200  tons  daily  easily  in  an 
emergency,  with  the  use  of  additional  dynamos  only,  it 
has  never  reached  this  maximum,  and  is  now  producing 
at  the  rate  of  84  tons  of  electrolytic  copper  daily. 

In  refining  copper  in  Anaconda  we  have  to  consider  the 
high  price  of  labor,  which  amounts  to  nearly  $3  on  an 
average  per  day  per  man.  The  cost  of  fuel  varies  between 
$2.50  and  $7  per  ton,  according  to  quality.  Sulphuric  acid 
costs  2.4  cents  per  pound  in  Anaconda,  and  other  supplies 
are  correspondingly  high  in  price.  We  can  safely  state  that 
expenses  in  Anaconda  are  generally  about  twice  those  at 
Eastern  industrial  centers.  The  refining  work  at  Anaconda, 
according  to  Thofehrn,  costs  no  less  than  $14  per  ton  of 
copper  produced,  including  the  saving  and  refining  of  the 
gold  and  silver  slimes. 

The  total  number  of  men  employed  in  the  Anaconda 
refinery  is  120,  inclusive  of  foreman,  assayers,  and  clerks. 
While  but  25  men  are  employed  in  the  newer  section  of  the 
refinery  for  a  daily  output  of  50  tons,  the  older  section 
requires  about  50  men  to  refine  the  same  quantity  of  copper, 
as  the  old  tank-house  was  considered  too  weak  to  allow 
of  the  installation  of  all  the  modern  improvements  and 


•98  MODERN  ELECTROLYTIC  COPPER  REFINING. 

conveniences  employed  in  the  newer  plant.  In  actual  prac- 
tice the  combined  output  of  both  sections  may  be  put  at 
100  tons  daily,  although  there  is  sufficient  tankage  capacity 
for  200  tons,  and  the  latter  figure  may  be  reached,  accord- 
ing to  Thofehrn,  by  simply  increasing  the  electric  current. 

The  electrolytic  copper  produced  at  Anaconda  averages 
98%  in  conductivity,  Matthiesson  standard;  it  has  a  tensile 
strength  of  64,000  to  65,000  Ib.  per  sq.  in.,  can  stand  80 
twists  in  6  in.  of  No.  12  wire  before  breaking,  and  has  an 
elongation  of  i^%.  All  these  measurements  were  taken  on 
hard-drawn  wire. 

The  anodes  delivered  to  the  refinery  contain  about  2% 
impurities,  which,  during  the  process  of  refining,  go  partly 
into  the  liquid  and  partly  into  the  slimes.  The  impurities 
which  enter  the  electrolyte  are  partially  taken  out  on  each 
turn  of  the  electrolyte  through  the  tanks.  A  certain  amount 
of  the  impurities  is  allowed  to  stay  in  the  liquid,  however, 
while  the  purification  process  is  regulated  so  as  to  limit 
the  accumulation  of  these  impurities  only.  The  simple 
purification  process  used  at  Anaconda,  necessitating  the 
use  of  air  and  cheap  chemicals  only,  is  claimed  to  be  superior 
to  the  old  process  of  crystallizing,  which  is  used  in  almost 
all  Eastern  refineries  in  treating  impure  solutions. 

The  Anaconda  Co.  in  1896  produced  about  350,000  oz. 
of  silver  in  bullion  999  fine  and  about  1500  oz.  of  gold  as 
bullion  950  fine  per  month  from  slimes  obtained  in  their 
copper  refinery.  These  slimes  were  sent  to  the  silver  mill 
in  lead-lined  tank  cars  and  treated  as  follows:  They  were 
first  hoisted  up  to  screens,  washed  with  water,  and  all  chips 
of  copper,  etc.,  taken  out.  The  partly  cleaned  silver  mud 
was  then  run  out  into  boiling  tanks,  where  it  was  freed  from 
its  copper  contents,  as  well  as  most  of  its  arsenic  and  anti- 
mony, by  boiling  with  acid  and  steam.  After  running  it 
on  a  filter  and  thoroughly  washing  it  with  water,  the  mud 
was  transferred  to  large  cast-iron  pans  and  dried.  A  con- 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  99 

sequent  melting  and  refining  in  a  reverberatory  furnace 
reduced  it  to  ingots  or  plates  ready  for  the  parting  kettles. 
The  furnace  was  charged  with  about  two  tons  of  the  dried 
silver  mud  at  a  time,  and  after  this  was  melted  as  rapidly 
as  a  wood  fire  would  permit,  it  was  refined  and  tapped  into 
molds  which  moved  on  a  small  train  in  front  of  the  furnace. 
The  ingots  or  plates  were  then  placed  in  the  parting  kettles, 
in  which  they  were  boiled  with  sulphuric  acid.  The  silver 
sulphate  obtained  was  siphoned  off,  diluted  with  water  and 
silver  from  the  solution  precipitated  on  copper  plates.  The 
pure  cement  silver  thus  obtained  was  thoroughly  washed, 
dried,  and  melted  into  ingots  in  furnace  charges  of  two 
tons  each.  The  ingots,  weighing  about  1200  oz.  each,  were 
assayed,  numbered,  weighed,  and  shipped  away  as  bullion, 
generally  999  points  fine.  The  gold  was  allowed  to  accumu- 
late in  the  parting  kettles  for  a  month,  when  it  was  taken 
out,  boiled  in  acid,  washed,  dried,  and  melted  down  into 
ingots,  together  with  suitable  fluxes. 

The  above  slime-refining  plant  or  silver  mill  was  re- 
modelled later,  but  the  cost  of  producing  fine  silver  and 
gold  still  remained  very  high.  The  slimes  are  at  present 
(Sept.,  1902)  shipped  in  paper-lined  boxes  to  the  Seattle 
Smelting  &  Refining  Co.'s  works  on  Puget  Sound  and  sold, 
as  they  can  be  refined  there  much  cheaper  than  this  could 
be  done  at  Anaconda.  The  actual  cost  of  refining  at  Seattle 
Is  not  more  than  i  cent  per  ounce  of  precious  metals  in  the 
slimes.  Contracts  have  been  closed,  I  believe,  by  which  the 
Seattle  refiner  pays  for  98%  of  the  silver,  all  of  the  gold 
at  $20  per  oz.,  and  the  copper  in  the  slimes  at  the  market 
price  less  6  cents. 

4.  Nichols  Refinery. 

The  Nichols  Chemical  Co.  is  operating  electrolytic  works 
in  Brooklyn,  N.  Y.,  of  an  estimated  daily  capacity  of  120 
tons  of  electrolytic  copper.  There  are  probably  six  gener- 


ioo  MODERN  ELECTROLYTIC  COPPER  REFINING. 

ators,  each  of  75  kw.  capacity  in  the  plant,  and  120  tanks, 
placed  in  multiple  series,  with  the  plates  therein  arranged 
according  to  the  series  system.  The  tanks  are  16  ft.  long, 
5  ft.  deep,  and  5.5  ft.  wide,  and  built  up  of  i-in.  thick  and 
4-in.  wide  planking.  The  anodes  are  from  0.25  in.  to  0.38  in. 
thick,  4^  ft.  long,  and  10  in.  wide,  and  weigh  about  65  Ib. 
each.  They  are  hammered  straight  by  hand,  and  are  sus- 
pended abreast  in  each  tank,  6  anodes  forming  a  row  and 
about  ioo  rows  filling  a  tank.  As  the  rows  are  spaced  about 
•J  in.  apart,  the  drop  in  potential  between  any  two  rows 
is  probably  as  low  as  from  o.i  to  0.2  volt. 

A  serious  drawback  in  the  series  system  as  applied  at 
the  Nichols  Works  lies  in  the  much  larger  quantity  of  scrap 
copper,  said  to  be  25%  to  30%  of  the  weight  of  the  anodes, 
produced  with  this  process  than  with  the  ordinary  multiple 
system,  although  it  possesses  several  advantages  over  the 
latter,  such  as  the  lower  first  cost  of  plant,  and  the  smaller 
amount  of  electrical  power  required  per  ton  of  output. 

5.  Baltimore  Copper  Works. 

The  Baltimore  Copper  Works,  operated  by  the  Balti- 
more Smelting  &  Rolling  Co.,  comprise  two  refineries, 
located  at  Canton  suburb,  Baltimore,  Md.  Their  total 
output  is  estimated  at  about  80  tons  and  their  capacity 
ioo  tons  of  electrolytic  copper  daily.  Eleven  80  kw.  gen- 
erators furnish  the  required  depositing  current,  which  is 
supplied  to  about  540  tanks.  The  tanks  in  the  smaller 
of  the  two  refineries  are  arranged  according  to  the  multiple 
system,  while  those  of  the  larger  or  Hayden  plant  are  dis- 
posed according  to  the  series  or  Hayden  system,  fully  dis- 
cussed heretofore  under  the  caption:  "Comparison  of 
Refining  Methods. ' '  In  the  multiple  plant  tanks  of  wood 
lined  with  lead  which  is  itself  protected  by  wooden  boards 
soaked  in  paraffin,  are  used,  while  in  the  series  system 


~ 


DESCRIPTION  AND    VIEWS  OF  REFINING   WORKS. 


101 


tanks  of  heavy  slate  coated  with  tar,  which  last  longer, 
but  are  much  more  expensive  than  wooden  tanks,  are 
•employed.  The  multiple  anodes,  cast  of  blister  copper  1.25 
in.  thick,  are  supported  by  lugs  of  phosphor  bronze. 

Pierce 's  semi-mechanical  casting  apparatus,  shown  in 
Fig.  42,  and  Walker's  casting  machines,  illustrated  in 
Figs.  37  and  38,  were  first  applied  at  these  works. 

Fig.  43  is  a  photographic  view  of  the  tank-house  of  the 
Hay  den  plant. 

Fig.  44,  the  interior  of  the  furnace-house,  while  Figs. 
45,  46,  47,  48,  and  49  show  details  of  the  electrolytic  appa- 
ratus employed  in  the  Hayden  system. 


FIG.  45. — Section  of  Hayden  Tank. 


FIG.  48. — Section  of  Siphon. 


FIG.  46. — Enlarged  Section 

showing  Anodes  with 

Deposited  Copper. 


FIG.  47.  —  Transverse  Section 

of  Hayden  Tank  showing 

Anodes. 


FIG.  49.  —  Grooved 
Slide. 


Details  of  the  Electrolytic  Apparatus  Employed  in  the  Hayden  System 

The  silver  slimes  obtained  as  a  by-product,  after  screen- 
ing, are  treated  in  lead-lined  tanks  with  dilute  sulphuric 


102  MODERN  ELECTROLYTIC  COPPER  REFINING. 

acid  (i  part  of  acid  to  4  parts  of  water)  and  air  drawn  in 
by  a  Korting  steam  injector  during  three  or  four  hours. 
In  this  short  space  of  time  the  greater  portions  of  the  arsenic, 
antimony,  copper,  and  other  impurities  are  dissolved,  and 
are  then  removed  by  siphoning  off  the  solution  from  the 
partly  purified  slimes.  As  the  slimes  contain  lead  sul- 
phate and  tellurium,  a  little  bismuth  and  antimony,  and 
the  gold  in  a  loose  form  unsuitable  for  economic  parting, 
they  are  melted  on  a  cupel  hearth,  at  first  without  any  flux. 
A  small  quantity  of  a  brownish  slag  carrying  about  20% 
of  lead  and  less  than  10%  of  antimony  is  then  skimmed 
off,  cooled,  and  picked  over,  so  as  to  save  the  larger  silver 
prills  it  contains.  It  is  eventually  added  to  molten  lead 
(scrap,  injured  tank  lining,  etc.)  in  a  cupelling  furnace. 
Here  the  lead  takes  up  most  of  the  gold  and  silver  in  the 
slag,  and  is  concentrated  until  its  contents  reach  about 
60%  of  silver,  while  a  slag  is  raked  off  which  is  poor  enough 
to  be  sent  to  a  blast-furnace  for  reduction  of  its  lead  con- 
tents. 

The  second  stage  of  the  melting  of  the  slimes  consists  in 
adding  about  100  Ib.  of  niter  to  the  metal  bath  and  skim- 
ming off  a  second  slag.  This  slag  is  very  rich  in  tellurium, 
containing  as  much  as  20%,  which  could  easily.be  extracted 
from  the  tellurite  of  sodium  formed,  so  as  to  obtain  possibly 
100  oz.  daily  if  there  were  any  large  demand  for  tellurium. 
The  silver  metal  on  the  cupel  now  being  practically  free 
from  impurities  outside  of  a  little  copper,  is  cast  into  dore 
bars  to  be  parted  in  the  usual  way. 

Finally  the  copper  contained  in  the  dilute  acid  solution 
obtained  in  removing  the  arsenic,  antimony,  etc.,  from  the 
impure  slimes  is  precipitated  by  scrap  iron  and  the  pre- 
cipitate is  melted  into  impure  copper  bars,  w^hich  are  sold 
or  given  special  treatment. 


DESCRIPTION  AND   VIEWS  OF  REFINING    WORKS.  103 


6.  Great  Falls  Refinery. 

This  plant,  belonging  to  the  Boston  and  Montana  Cons. 
Copper  and  Silver  Mining  Co.,  now  a  part  of  the  Amal- 
gamated Copper  Co.,  at  Great  Falls,  Montana,  produces 
approximately  75  tons  of  electrolytic  copper  daily.  Two 
810  kw.  generators,  turbine  driven,  furnish  the  current  to 
the  tank-house,  located  about  500  yd.  distant  from  the 
falls  at  Black  Eagle  dam,  through  huge  conductors  of  cast 
copper  8  or  10  in.  wide  and  2  in.  thick. 

There  are  324  depositing  tanks  in  the  refinery,  each 
containing  20  cathodes  and  21  anodes,  arranged  in  multiple 
circuit.  A  current  of  high  amperage  (9000  amperes)  is 
used  at  Great  Falls,  because  ample  and  cheap  power  is 
provided.  The  density  of  the  current  is  maintained,  ac- 
cording to  report,  at  from  30  to  40  amperes  per  square 
foot  of  cathode  surface.  This  seems  a  dangerously  high 
density  to  employ  when  good  deposits  are  desired,  although 
it  enables  the  refiner  to  reduce  the  time  required  in  turning 
out  a  given  weight  of  cathodes  to  one-half,  or  one-third, 
of  the  time  usually  necessary.  Moreover,  such  high  den- 
sities are  only  practicable,  it  is  believed,  when  the  anodes 
to  be  refined  are  comparatively  low  in  silver  and  gold,  as 
at  Great  Falls,  and  the  solutions  are  kept  comparatively 
clear  and  pure.  The  tank  conductors  are  about  6  in.  wide 
and  2  in.  thick. 

The  anodes  are  cast  direct  from  the  large  converters 
employed  in  the  Boston  and  Montana  smelter,  that  is,  the 
anodes-  are  made  from  copper  poured  from  ladles  filled 
from  the  converters,  and  not  from  reverberatory  anode 
furnaces,  as  is  the  usual  practice. 

J.  T.  Morrow,  the  superintendent  of  the  Great  Falls 
refinery,  devised  what  he  deems  to  be  an  improved  anode, 
and  invented  the  following  form  of  mold  for  casting  such 


104 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


anodes.      The  nature  of  this  invention  will  best  be  under- 
stood from  a  description  of  the  -accompanying  cuts. 

Fig.  50  is  a  plan  view  of  the  mold;  Fig.  51  a  cross-sec- 
tion on  the  plane  2  2  of  Fig.  50;  Fig.  52  a  detail  view  show- 
ing a  portion  of  the  mold  and  clip-holder  in  place;  Fig.  53 
a  cross-section  of  Fig.  52  on  the  plane  4  4;  Fig.  54  an  edge 
elevation  of  one  of  the  clip-holders,  and  Fig.  55  shows 
in  cross-section,  on  a  plane  corresponding  to  2  2  of  Fig.  50, 
the  anode  and  its  retaining-clip. 


J.  T.  Morrow's  Mold  for  Casting  Anodes. 

The  anode  B,  Fig.  55,  is  of  cast  metal  and  provided 
with  clips  C  of  sheet  metal,  so  formed  that  the  ends  D  are 
cast  into  the  anode  and  thereby  secured.  The  mold  E 
for  casting  the  anode  is  shaped  to  the  form  required — such, 
for  instance,  as  shown  in  Fig.  50 — having,  preferably,  two 
lug-forming  portions  F.  The  wall  K  of  the  mold  is  much 
lower  at  the  points  G  than  at  the  other  points  and  forms 
a  low  dam,  upon  which  the  ends  D  of  the  clips  C  rest,  as 
seen  in  section  in  Fig.  53.  A  holder-block  H  is  then  placed 
on  each  clip  and  is  adapted  to  fit  snugly  about  the  ends  D 


DESCRIPTION  AND  VIEWS  OF  REFINING   WORKS.  105 

•of  the  clip  and  form  a  continuation  of  the  wall  of  the  mold 
above  the  dam  or  bridge  6",  so  as  to  confine  the  molten 
metal,  while  allowing  the  ends  of  the  clips  D  to  project 
into  the  molten  metal  and  be  thereby  cast  into  the  anode. 
Morrow  prefers  to  arrange  the  holder-block  and  adjacent 
parts  in  the  way  shown  in  the  drawings — that  is  to  say,  he 
provides  projecting  portions  I  on  the  mold  E  outside  the 
low  wall  or  dam  6",  and  fits  the  weights  or  holders  for  the 
clips  to  these  projections  or  extensions  L,  so  that  when  in 
place  the  downwardly  projecting  lugs  M  lie  on  either  side 
of  the  extensions  and  insure  the  proper  placing  of  the  clip- 
holders.  The  clip-holders  are  also  provided  with  a  down- 
wardly extending  edge  or  dam  0,  which  comes  opposite  and 
registers  properly  with  the  dam  G,  leaving  room  enough 
between  for  the  ends  D  of  the  clips  C. 

In  using  such  a  mold  and  clip-holder  the  clips  are  first 
laid  in  position  and  the  holders  then  placed  upon  them. 
The  molten  metal  is  then  poured  into  the  mold  E  and  flows 
into  the  lug-forming  recess  F  of  the  mold.  It  surrounds 
and  embeds  the  ends  D  of  the  clips,  but  is  held  in  check 
by  the  fixed  dam  G  and  removable  clip-holders//.  As 
soon  as  the  metal  has  cooled  it  is  taken  from  the  mold, 
with  the  clips  C  secured  to  it,  as  shown  in  Fig.  55. 

If  an  anode  breaks  at  or  near  its  slugs  during  refining, 
it  is  hung  upside  down  from  the  supporting  bar  on  two 
copper-ring  hooks  passing  through  holes  drilled  through 
the  defective  anode.  The  quantity  of  scrap  copper  pro- 
duced is  thereby  reduced. 

The  following  ingenious  machine  for  fastening  flat  loops 
on  cathode  sheets  to  secure  a  better  method  of  their  sus- 
pension than  the  method  heretofore  used  was  also  designed 
by  J.  T.  Morrow. 

From  cathode  sheets,  which  are  from  -gV  to  o.  i  in.  thick, 
strips  about  10  in.  long  and  3  in.  wide  are  cut,  bent  at  the 
middle,  and  together  with  the  trimmed  cathode  sheets 


io6  MODERN  ELECTROLYTIC  COPPER  REFINING. 

fed  by  hand  into  the  fastening  machine.  The  latter  first 
slits  both  the  sheets  and  the  loop  at  one  stroke  and  in  a 
designated  spot  in  the  shape  of  a  cross,  and  then  by  means 
of  a  punch  laps  the  double  flaps  produced  by  the  slitting 
process  over  the  cathode  sheet,  so  as  to  make  a  secure  fas- 
tening. The  sheets  can  now  be  hung  in  the  tanks  by  simply 
passing  a  copper  rod  through  their  two  supporting  loops. 
As  the  entire  face  of  the  cathode  is  thus  made  to  hang 
within  the  liquid,  its  active  surface  is  increased,  and  the 
circulation  of  the  electrolyte  at  its  top  is  not  impeded,  an 
important  advantage  over  the  usual  method  of  suspend- 
ing cathodes,  which  consists  in  bending  their  entire  upper 
ends  in  a  roll  over  the  supporting  bars. 

Circulation  of  the  electrolyte  is  effected  by  a  terrace 
arrangement  of  the  successive  tanks,  with  a  difference  of 
about  2  in.  in  level  between  the  latter,  and  the  use  of  large 
connecting  pipes.  There  is  a  complete  renewal  of  the 
solution  in  a  tank,  say,  every  three  hours.  In  raising  the 
electrolyte  from  the  receiving  pump,  direct-acting  plunger 
pumps  provided  with  improved  rubber  bucket  lifts  are 
used,  together  with  *  *  Monte  jus ' '  or  pressure  tanks  of  the 
usual  construction. 

The  following  interesting  method  of  purifying  the  elec- 
trolyte is  reported  as  being  used  with  success  at  Great 
Falls.  It  consists  in  treating  the  solution  to  be  purified 
in  special  tanks  and  precipitating  the  impurities,  chiefly 
arsenic  and  antimony,  together  with  considerable  copper, 
more  or  less  loosely  on  copper  cathodes  placed  opposite 
lead  anodes,  by  very  strong  currents.  There  are  12  lead- 
lined  purifying  tanks  (3  sets  of  4  each)  to  288  refining  tanks, 
covered  with  hoods  to  carry  off  escaping  fumes.  The 
cathodes  are  about  o.i  in.  thick,  30  in.  wide,  and  36  in. 
long,  while  the  anodes  are  lead  sheets  of  about  the  same 
size  sweated  on  to  the  copper  rods  which  support  the  plates. 
The  precipitated  impurities  and  copper  partly  hang  on  the 


DESCRIPTION  AMD   VIEWS  OF  REFINING   WORKS.  107 

cathodes  and  partly  drop  to  the  bottom  of  the  vats.  These 
are  cleaned  out  about  every  two  months  and  the  accumu- 
lated arsenical  and  antimonial  mud,  carrying  from  40%  to 
60%  copper,  removed.  The  mud  is  finally  reduced  to  im- 
pure bars  in  one  of  the  refining  furnaces  in  the  works. 

When  the  cathodes  have  become  thickly  incrusted  with 
impurities  or  are  otherwise  rendered  useless,  they  are 
melted  down  into  cake  copper  or  into  certain  brands  of 
ingot  copper,  in  which  a  small  percentage  of  arsenic  and 
antimony  is  said  to  be  of  little  consequence,  if  it  is  not  of 
direct  advantage  in  increasing  the  fusibility  of  the  copper. 

The  electrolyte  purified  by  the  above  process  is  restand- 
ardized,  returned  to  the  refining  tanks,  and  continued  in 
regular  use  until  it  has  become  so  highly  charged  with  iron 
salts,  etc.,  as  to  interfere  with  the  copper  deposition  or 
cause  the  depositing  copper  to  blacken.  In  that  case  only 
is  the  refinery  solution  withdrawn  from  circulation  and 
pumped  to  the  blue  vitriol  works,  so  that  the  amount  of 
blue  vitriol  which  it  is  necessary  to  handle  in  the  works 
is  kept  down  to  a  minimum. 

Although  an  average  of  75  tons  of  refined  copper  are 
produced  daily  in  the  above  refinery,  it  is  reported  that 
only  about  20  men,  drawing  wages  of  from  $2.25  to  $2. 75 
per  diem,  are  regularly  employed  in  the  tank-room. 

7.  Balbach  Refinery. 

This  electrolytic  refinery,  operated  by  the  Balbach 
Smelting  and  Refining  Co.,  at  Newark,  N.  J.,  is  the  oldest  in 
the  United  States.  It  was  started  early  in  the  eighties  and 
is  still  in  active  operation,  with  an  output  at  present  of 
about  45  tons  and  a  capacity  of  50  tons  of  electrolytic 
copper  daily,  produced  with  two  i25-kw.  generators  and 
one  of  3oo-kw.  capacity;  430  electro-depositing  tanks  are 
employed. 


io8  MODERN  ELECTROLYTIC  COPPER  REFINING. 

The  Balbach  anodes  are  cast  36  in.  long,  24  in.  wide, 
and  i  in.  thick,  each  having  a  long  and  a  short  lug,  and 
weighing  from  300  to  400  Ib. 

The  cathodes  are  electro-deposited  thin  sheets  of  copper, 
36  in.  long  and  24  in.  wide,  bent  over  copper  suspending 
bars,  whose  bent-up  ends  rest  on  the  tank  walls  or  con- 
ductors. 

Twenty  anodes  and  as  many  cathodes  are  placed  in  a 
tank.  The  plates  are  all  in  multiple  circuit  and  the  tanks 
in  series.  As  the  tanks  are  all  on  the  same  level,  the  circu- 
lation of  the  electrolyte  is  effected  by  overflow  through 
I -in.  lead  pipes  to  launders  placed  below  the  floor  level 
and  feeding  in  the  solution  through  lead  pipes  from  an 
overhead  feed  launder  near  the  middle  of  a  group  of  four 
tanks,  each  of  the  four  branches  of  the  vertical  feed  pipe 
supplying  a  tank  with  solution. 

The  tanks  are  about  9  ft.  long,  3  ft.  wide,  and  4  ft.  deep, 
constructed  of  3-in.  plank  and  lead  lined,  two  tanks  being 
placed  side  by  side,  with  one  mutual  dividing  partition, 
and  two  with  abutting  ends,  so  that  four  tanks  form  a  single 
group. 

All  the  positive  electrodes  of  a  tank  are  placed  in  the 
same  plane  with  the  negative  electrodes  of  the  side-ad- 
joining tank  and  vice  versa,  but  the  anode  lugs  of  the  first 
tank  are  insulated  from  the  cathode  bars  of  the  second, 
when  the  cathode  bars  of  the  first  are  electrically  connected 
to  the  anode  lugs  of  the  second,  and  vice  versa.  The  con- 
nectors are  flat  pieces  of  copper  used  as  supports.  Light 
boards  4  or  5  in.  wide  are  placed  over  all  the  connections 
so  as  to  protect  them  from  any  dripping  solution  when  the 
electrodes  are  lifted  out  of  the  tanks.  The  conductors 
are  copper  bars  4  in.  by  0.75  in.  in  section,  each  bar  being 
long  enough  to  extend  the  length  of  the  two  tanks  along- 
side of  which  it  is  placed.  The  bars  are  so  arranged  that 
their  polarity  alternates  on  the  same  side  of  a  row  of  tanks. 


DESCRIPTION  4ND   VIEWS  OF  REFINING   WORKS.  109 

In  the  latter  a  current  density  of  12  to  16  amperes  per  sq. 
ft.  of  cathode  surface  is  maintained. 

At  the  foot  of  each  double  row  of  tanks  are  placed  two 
washing  tubs  for  cleaning  the  anodes,  and  running  over 
each  double  row  are  two  lines  of  overhead  rails  with  tackle 
for  lifting  purposes. 

The  slimes,  containing  silver,  gold,  bismuth,  sand,  etc., 
are  cleaned  up  continuously,  and  the  dore  bullion  eventually 
obtained  is  parted  electrolytically. 

When  very  impure  copper  is  treated,  the  electrolyte  may 
carry  as  much  as  7  to  8  g.  of  arsenic  per  liter,  and  yet  good 
cathodes  for  wire  bars  have  been  produced  from  anode 
material  running  as  high  as  5%  in  arsenic. 

Regeneration  of  the  solution  is  effected  by  periodically 
running  off  a  portion  of  the  electrolyte  and  replacing  it  by 
fresh  solution.  The  copper,  iron,  and  nickel  sulphates  are 
crystallized  out  from  the  portion  withdrawn,  and  the  mother 
liquor  is  boiled  down  so  as  to  obtain  arsenic  salts,  arsenious 
acid,  etc.  If  the  electrolyte  carries  much  antimony,  part 
of  it  precipitates  as  what  appears  to  be  gray  antimonious 
oxide  in  the  tank  discharge  launders. 

The  small  quantities  of  nickel  contained  in  the  blister 
copper  treated,  and  which  concentrate  in  the  acid  electro- 
lyte, are  recovered  as  nickel  salts  by  repeated  fractional 
crystallization  of  the  combined  salts  and  a  final  removal  of 
the  remaining  copper  by  electrolysis.  The  Balbach  Co.  was 
a  pioneer  in  this  method  of  producing  nickel-platers'  salts, 
for  which  it  has  found  a  ready  market  ever  since  1891. 
Under  the  long  and  efficient  superintendence  of  Mr.  F.  A. 
Thum  and  his  son,  Wm.  Thum,  it  was  also  the  first  firm  to 
introduce  and  successfully  operate  the  multiple  system  of 
electrolytic  copper  refining  in  America,  and  employ  the 
appliances  and  methods  now  generally  used  by  electrolytic 
refiners.  An  ingenious  tilting  anode  mold,  designed  by  F.  A. 
Thum,  is  in  use  at  the  Balbach  Works.  It  consists  of  a 


no  MODERN  ELECTROLYTIC  COPPER  REFINING. 

fixed  standard  with  journals  upon  which  the  mold  is  piv- 
oted and  may  be  rotated.  The  mold  itself  is  made  up  of 
two  pieces:  the  anode  mold  proper,  of  the  usual  form  for 
casting  anodes,  provided  with  a  long  and  a  short  lug,  and  a 
separate  piece  with  beveled  edge,  for  forming  the  upper  or 
head  rim  of  the  anode,  which  piece  retains  its  place  as  long 
as  the  mold  is  kept  in  a  horizontal  position,  and  is  hinged 
to  the  mold  proper.  When  pouring  copper  into  the  mold, 
the  latter  is  kept  from  turning  over  and  discharging  its 
contents  by  a  clip,  which  is  released  as  soon  as  the  copper 
lias  set.  The  weight  of  the  filled  mold  then  causes  it  to  tilt 
over  and  the  head-piece  to  strike  against  the  standard, 
whereupon  it  reacts  in  such  a  way  that  the  weight  of  the 
anode  itself  forces  out  the  head-piece  by  wedging  against 
the  beveled  edge  of  the  latter  and  finally  allows  the  anode 
to  slide  from  its  mold  into  a  truck  or  conveyor  placed  ready 
to  receive  it. 

8.  De  Lamar  Refining  Works. 

These  works,  located  near  Cartaret,  N.  J.,  refine  blister 
copper  from  the  Bully  Hill  Mines  of  California  and  the 
Tacoma  Smelting  and  United  States  Mining  Companies,  and 
have  a  capacity  for  treating  50  tons  daily.  Current  is  fur- 
nished by  one  52o-kw.  generator.  The  number  of  tanks  is 
estimated  at  408,  and  their  arrangement  is  probably  like 
that  of  the  new  Perth  Amboy  refinery  of  the  American 
Smelting  and  Refining  Co.,  as  a  royalty  is  being  paid  by  the 
De  Lamar  Works,  I  understand,  to  Mr.  A.  L.  Walker  for 
the  use  of  his  patented  arrangement  of  plant.  About  10,000 
oz.  of  silver  and  200  oz.  of  gold  are  obtained  daily  in  treat- 
ing the  slimes  separated  from  the  copper. 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  1 1 1 

...      -v 

9.   The  Buffalo  Refinery. 

This  plant  forms  part  of  the  Buffalo  Smelting  Works, 
located  in  the  Black  Rock  section  of  Buffalo,  N.  Y.,  and  con- 
sists of  an  old  and  a  new  refinery. 

At  the  Buffalo  Copper  Works  about  60%  of  the  Calumet 
and  Hecla  Co.'s  enormous  production  of  native  copper  con- 
centrates is  refined,  argentiferous  copper  material  running 
at  least  15  oz.  silver  per  ton,  being  melted  down  and  cast 
into  plates,  which  are  sent  to  the  electrolytic  works.  Prac- 
tically all  of  the  silver  in  the  crude  copper  passes  into  the 
slimes  or  tank  mud,  and  is  periodically  recovered  by  boiling 
the  silver  mud  with  sulphuric  acid  to  remove  the  bulk  of 
the  impurities,  refining  it  on  a  small  furnace  hearth  and 
casting  the  silver  into  bars  weighing  about  1000  oz.  each. 
The  absence  of  gold  from  the  argentiferous  copper  obtained 
by  reducing  the  native  copper  ores  of  Michigan  is  remark- 
able and  greatly  simplifies  the  silver-parting  process. 

The  old  refinery  contains  269  lead-lined  tanks,  approxi- 
mately 10X3X3  ft.  in  size.  Its  daily  output  is  6  tons  of 
electrolytic  copper,  with  a  current  measuring  about  47  volts 
and  600  amperes.  A  current  density  of  only  three  amperes 
per  square  foot  of  the  cathode  surface  is  used  at  Buffalo, 
as  the  management  find  it  advantageous  not  to  push  the 
refining  capacity  of  the  electrolytic  plant,  especially  as  the 
cost  of  the  power  required  quadruples  with  the  doubling 
of  the  current  density.  Each  anode  plate  weighs  about 
280  lb.,  and  is  cast  about  1.6  in.  thick  at  top,  with  three 
longitudinal  strengthening  ribs  cast  in,  as  ribbed  anodes 
were  found  to  hold  together  better  than  plain  ones.  The 
starting  sheets  are  formed  by  deposition  on  both  sides  of 
copper  plates  lightly  washed,  it  is  said,  with  a  dilute  solu- 
tion of  iodine  in  naphtha. 

The  new  40-ton  electrolytic  copper  refinery,  built  east 
of  the  old  works,  is  furnished  with  power  by  a  Mclntosh- 


H2  MODERN  ELECTROLYTIC  COPPER  REFINING. 

Seymour  engine,  driving  a  Crocker- Wheeler  generator,, 
which  is  guaranteed  to  deliver  a  current  of  300  volts  and 
1700  amperes  when  running  at  a  speed  of  126  revolutions 
per  minute.  There  are  reported  to  be  490  tanks  in  the  new 
refinery,  with  a  basement  underneath  the  tank  floor  to  facili- 
tate inspection  for  leakages  and  emptying  of  the  tanks.  The 
circulation  of  the  electrolyte  is  effected  by  a  cascade 
arrangement  of  the  tanks  instead  of  on  a  level,  as  in  the  old 
refinery,  the  solution  being  pumped  to  the  highest  row  of 
tanks  and  gravitating  downwards.  The  anodes  measure  29  in. 
long,  27  in.  wide,  and  about  i  in.  thick,  and  are  provided 
with  small  lugs  on  top  instead  of  large  side  lugs,  which  were 
formerly  used.  Electric  traveling  cranes  and  racks  similar 
to  those  in  use  at  the  Raritan  refinery  will  be  used  for 
charging  the  tanks  with  plates  and  removing  the  cathodes. 

Each  heat  of  refined  copper  is  tested  for  the  mechanical 
properties  and  for  the  electrical  conductivity  of  the  copper 
as  follows:  Representative  sample  bars  weighing  about 
one  pound  each  are  cast  at  the  pouring  of  every  furnace 
charge.  Pieces  of  sufficient  length  from  these  sample  bars 
are  passed  through  small  rolls  and  annealed  at  a  dull-red 
heat  in  the  muffle  of  an  assay  furnace  whenever  they  be- 
come too  hard.  They  are  then  pickled  in  dilute  sulphuric 
acid,  washed  in  water  and  passed  through  successive  dies, 
finally  being  drawn  into  wire  about  0.125  in.  in  diameter. 
These  wires  are  numbered  and  constitute  the  samples 
used  in  the  Siemens  apparatus  for  making  the  conductiv- 
ity tests.  Good  annealed  copper  wire  0.125  in.  diameter 
should  possess  a  conductivity  of  at  least  98%,  should 
stand  about  55  twists  before  breaking,  and  should  show  a 
tensile  strength  of  not  less  than  24  tons  per  square  inch  of 
cross-section,  according  to  the  usual  standard. 

The  cost  of  electrolytic  refining  at  the  Buffalo  works  is 
reported  not  to  exceed  o.3C.  per  Ib.  of  crude  copper,  with 
current  delivered  at  a  cost  of  $27  per  H.P.  per  year. 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS. 


10.  Blue  Island  Refinery. 

This  electrolytic  plant,  at  Blue  Island,  111.,  is  operated 
by  the  Chicago  Copper  Refining  Co.  It  produces  on  an  aver- 
age 5  tons  of  electrolytic  copper  per  day  with  two  64-kw. 
generators,  delivering  current  to  250  tanks  arranged  in 
series,  with  plates  in  multiple. 

The  circulation  of  the  electrolyte  is  either  effected  by 
means  of  two  Monte  jus  or  collecting  tanks,  which  are  used 
alternately,  so  that  as  soon  as  one  is  full  it  is  automatically 
closed,  and  a  small  air-compressor  forces  the  solution  up 
to  the  distributing  tank  again,  or  the  circulation  is  effected 
by  means  of  one  pressure  tank,  by  using  a  three-way  valve, 
working  automatically,  which  increases  and  relieves  the 
pressure  in  this  tank  every  30  seconds.  A  circulation  of 
6  gal.  per  minute  has  been  found  convenient. 

The  Chicago  Copper  Refining  Co.  obtains  about  3.75  Ib. 
of  slimes  from  every  100  Ib.  of  anode  copper.  Formerly  the 
washed,  dried,  and  screened  mud  was  shipped  directly,  or 
first  melted  into  bars  to  avoid  losses  by  dusting,  and  then 
sold  to  lead  refiners,  but  it  is  now  treated  so  as  to  recover 
dore  bars,  which  are  parted,  to  secure  the  fine  metals,  in  the 
usual  way. 

B.  GREAT  BRITAIN. 

i.  Bottom's  Froghall  Refining  Works. 

By  JOHN  B.  C.   KERSHAW. 

This  refinery,  at  Froghall,  Staffordshire,  England,  and 
a  smaller  electrolytic  plant  at  Widnes,  in  Lancashire,  de- 
scribed in  subsequent  pages,  belong  to  the  firm  of  Messrs. 
T.  Bolton  &  Sons,  which  was  established  in  1783  and  had 
existed  as  a  private  company  until  June,  1902,  when  it 
was  registered  under  the  joint-stock  company  laws  as 
Messrs.  T.  Bolton  &  Sons,  Ltd.,  with  a  capital  of  $1,440,000. 


H4  MODERN  ELECTROLYTIC  COPPER  REFINING. 

The  combined  actual  output  of  the  Froghall  and  Widnes 
works  for  the  years  1892  to  1896  was  estimated  to  average 
7000  tons  per  annum.  Since  the  latter  year  no  official 
figures  are  available  for  publication.  It  is  reported  that  a 
portion  of  the  plant  at  Froghall  is  used  for  depositing  nickel 
and  tin,  but  no  authentic  information  can  be  obtained  from 
the  firm  on  this  point. 

The  electrical  power  at  the  Froghall  refinery  is  supplied 
by  four  275-H.P.  triple-expansion  engines  using  steam  at 
150  Ib.  pressure.  Each  engine  drives  two  dynamos  of  the 
Elwell-Parker  type  by  rope  gearing  (see  Fig.  56),  generat- 
ing 1500  amperes  at  50  volts.  The  total  capacity  of  this 

refinery  is,  therefore,  equal  to  — •  =600  kw. 

1000  . 

The  depositing  plant  at  Froghall  is  represented  by  550 
vats,  constructed  in  the  usual  manner  of  wood  lined  with 
lead,  each  measuring  48  in.  X3Q  in.  X42  in.  deep.  When 
fully  charged  each  vat  contains  10  anodes  and  9  cathodes, 
and  presents  a  total  depositing  surface  of  126  sq.  ft.  The 
vats  are  arranged  terrace-wise  in  order  to  facilitate  circu- 
lation, and  from  60  to  70  vats  are  worked  in  series.  The 
electrodes  in  each  vat  are  connected  in  parallel.  Under 
normal  working  conditions  4  Ib.  copper  are  deposited  per 
hour  in  each  vat,  and  the  maximum  output  of  the  Froghall 
works,  when  all  the  vats  are  in  use,  is  700  tons  copper  per 
month,  or  8400  tons  per  year. 

The  anodes  are  cast  from  copper  produced  at  the 
Widnes  works,  and  they  are  allowed  to  remain  in  the  vats 
six  weeks.  The  sludge  is  worked  for  silver  and  gold  in  the 
usual  manner. 

The  electrolytic  copper  obtained  at  this  refinery  is  re- 
melted,  and  is  then  worked  up  by  the  firm  into  wire  (at 
the  Oakamore  Wire  Works,  situated  near  the  Froghall 
Refinery),  boiler  tubes,  rolled  plate,  etc. 


If 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  11$ 

2.  Pembrey  Copper  Works. 

The  output  of  these  works,  belonging  to  Elliott 's 
Metal  Co.,  Ltd.,  Burry  Port,  South  Wales,  is  about  130 
tons  per  week.  The  number  of  vats  in  use  is  1065.  The 
electrodes  are  arranged  according  to  the  multiple  process, 
which  was  invented  by  Mr.  James  Elkington,  one  of  the 
proprietors  of  the  Pembrey  works,  and  was  first  installed 
on  a  commercial  scale  there  in  1869.  Elliott's  Co.  claims 
these  were  the  first  works  in  the  world  where  copper  by  this 
process  was  produced  commercially.  A  current  density 
of  10  amperes  is  employed.  Total  power  generated,  385 
kw. ;  size  of  anodes,  10  in.  wide  by  24  in.  long;  size  of 
cathodes,  4  in.  wide  by  24  in.  long;  voltage  per  vat,  0.3  volt. 

The  electrolyte  contains  9  Ib.  of  bluestone  and  4.5  Ib. 
of  free  acid  per  cubic  foot,  according  to  figures  kindly 
furnished  by  the  manager  of  the  works. 

3.  Bonn's  Widnes  Refinery. 

The  Widnes  plant,  known  as  the  Mersey  Copper  Works, 
of  Messrs.  T.  Bolton  &  Sons,  Ltd.,  is  used  for  refining  copper 
by  both  the  fire  and  the  electrolytic  process.  A  large 
portion  of  the  partly  refined  copper  produced  at  these 
works  is  sent  to  the  Froghall  refinery  for  electrolytic 
treatment. 

The  electrical  power  for  the  Widnes  depositing  plant  is 
provided  by  two  Galloway  engines,  which  drive  by  belt- 
gearing  (see  Fig.  57)  four  75-kw.  generators  of  the  Elwell- 
Parker  type.  When  running  at  500  revolutions  these  gen- 
erators deposit  about  11.5  long  tons  of  copper  per  156 
hours  (Gore). 

The  vats  (see  view  of  interior  of  tank-house,  Fig.  58) 
are  said  to  be  4  ft.  long,  2  ft.  6  in.  wide,  and  3  ft.  6  in.  deep, 
and  are  placed  in  rows  of  60  tanks  in  single  series,  with 


u6  MODERN  ELECTROLYTIC  COPPER  REFINING. 

gangways  between  rows.  The  current  passes  up  one  row, 
down  the  next,  etc.,  and  is  maintained  at  a  density  of  not 
exceeding  10  amperes  per  square  foot  of  cathode  surface. 
Each  loaded  tank  contains  10  anodes  and  9  cathodes, 
placed  in  parallel  circuit. 

The  anodes  consist  of  auriferous  and  argentiferous  "bot- 
toms," obtained  by  so-called  "bottom  smelting"  of  im- 
ported argentiferous  "regulus"  and  of  refined  "coarse" 
copper. 

In  March,  1897,  it  was  stated  that  Bolton's  Widnes 
refinery  was  producing  at  the  rate  of  300  tons  of  electro- 
lytic copper  per  month,  although  its  maximum  capacity 
under  normal  conditions  is  about  350  tons  monthly  or 
4200  tons  per  annum. 

4.  Leeds  Copper  Works. 

The  following  description  and  views  of  this  plant, 
owned  by  the  Leeds  Copper  Works,  Ltd.,  Leeds,  formerly 
the  English  Electro-Metallurgical  Co.,  Ltd.,  are  taken  from 
an  excellent  article  in  Engineering,  May  16,  1902,  which 
is  endorsed  by  the^  operating  company. 

The  works  are  situated  at  Hunslet,  Leeds,  on  the  site 
formerly  occupied  by  the  Elmore  works,  which  were  erected 
to  work  the  Elmore  patents  for  the  application  of  a  bur- 
nishing tool  to  copper  during  the  progress  of  the  electro- 
lytic deposition,  but  which  did  not  pay  for  various  rea- 
sons, although  not,  it  is  claimed,  through  any  inherent 
impracticability  in  the  processes. 

The  present  concern  has  taken  up  the  latter  and  the 
various  properties  of  the  old  Elmore  company,  and  is  now 
working  them  with  a  large  cash  capital,  and  satisfactorily, 
it  is  asserted. 

The  new  works  are  shown  on  the  plans,  Figs.  60  and  61. 
They  consist  chiefly  of  a  boiler  and  economizer  plant,  an 


I 

I 

I 

I 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS. 


117 


engine-  and  dynamo-house,  buildings  containing  copper 
furnaces,  a  tank-house  or  deposit  ing-room,  and  a  shop  con- 
taining draw-benches  and  other  machinery.  The  Leeds 


PRIVATE  ROAD  TO  LEEDS 


1 

p 

.,1;  :  '•./., 

Draw  Benches,  etc. 

a* 

Depositing  Shed 

2 

' 

nl      " "-"-"-•* 
Refiner, 
i      '.i.j 


FIG.  60  — Map  of  the  Leeds  Copper  Works. 

works  were  built  and  equipped  on  the  pattern  of  kindred 
works  in  France,  which  have  been  in  operation  for  some 
years  past  at  Dives,  in  Normandy. 

The  various  shops  at  present  cover  17  acres;  they  are 
connected  with  the  Leeds-Liverpool  Canal  and  with  the 
Midland  Railway. 

The  engine-room  is  shown  in  Fig.  62;  it  measures  215 
ft.  in  length  by  65  ft.  in  width,  and  contains: 

(a)  The  depositing  set  of  engines,  consisting  of  four 
pairs  of  250-!!. P.  Bollinck  cross-compound  condensing  Cor- 
liss engines.  The  high-pressure  cylinder  exhausts  into  a 
receiver  placed  underneath  the  engine-room;  the  receiver 
supplies  the  necessary  steam  to  the  low-pressure  cylinder, 
which  exhausts  into  the  condenser.  Each  pair  of  engines 
drives  by  belt  transmission  a  i7o-kw.  Brown-Boveri  gen- 
erator for  depositing. 

(6)   The  power  set,  formed  of  three  pairs  of  400-H.P. 


u8 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


o 

I 


DESCRIPTION  AND   VIEWS  OF  REFINING  WORKS.  119 

Bollinck  cross-compound  condensing  Corliss  engines,  similar 
in  design  to  the  above,  each  pair  of  which  drives  a  Brown- 
Boveri  dynamo  of  400-H.P.  at  525  volts,  and  running  at 
325  revolutions. 

(c)  The    lighting  set,  which  consists  of  two  300-H.P. 
Willans  high-speed  engines,  coupled  direct  to  Elwell-Parker 
dynamos. 

(d)  The  main  switchboard,  in  two  parts — one  for  de- 
positing and  the  other  for  power — and  the  lighting  switch- 
board. 

The  engines  are  supplied  with  steam  at  i4o-lb.  pressure 
per  square  inch,  from  seven  Galloway  300  horse-power 
boilers,  32  ft.  long  and  8  ft.  6  in.  in  diameter,  connected  to 
a  chimney  200  ft.  high  and  10  ft.  inside  diameter  at  top. 
They  are  fed  by  two  Worthington  feed-pumps.  The  feed- 
water  is  taken  from  the  canal,  but  previous  to  being  used 
in  the  boilers,  it  runs  through  a  pulsometer  "torrent" 
filter. 

The  boilers  work  in  conjunction  with  seven  economizers 
located  in  a  space  between  the  boiler-house  and  the  engine- 
room.  All  the  steam-pipes,  valves,  and  connections  are 
in  duplicate. 

The  copper  used  in  the  depositing  process  is  supplied  to 
the  works  in  the  shape  of  96%  Chili  bars  or  blister  copper; 
this  is  treated,  for  the  removal  of  arsenic  and  other  impuri- 
ties, in  three  refining  furnaces  of  12  tons  each.  The  refined 
copper  is  then  cast  into  trough-shaped  molds,  13  ft.  in 
length,  for  the  production  of  the  copper  anodes.  These  are 
triangular  in  section,  with  slightly  concave  sides  and  ver- 
tices rounded  off.  They  are  cleaned  with  sulphuric  acid 
and  water  previous  to  being  placed  in  the  depositing 
tanks. 

The  depositing  department  for  the  production  of  copper 
tubes  and  for  the  copper  coating  of  rolls,  is  illustrated  in 
Fig.  63.  It  is  located  in  a  building  265  ft.  long  and  200  ft. 


120  MODERN  ELECTROLYTIC  COPPER  REFINING. 

wide,  which  contains  216  acid  sulphate-depositing  tanks, 
in  24  rows  of  nine  tanks  placed  end  to  end.  Each  of  the 
six  bays  in  the  tank-house  therefore  covers  four  sets  of 
nine  tanks  each,  connected  in  pairs  side  by  side  for  their 
mechanical  operation.  The  plant  is  capable  of  a  total 
weekly  output  of  75  tons.  Two  electric  motors,  one  on 
each  side  of  the  depositing  room,  alternately  drive  an  under- 
ground main  shaft,  placed  underneath  the  front  end  of  the 
tank  rows.  Link  gearing,  driven  by  the  main  shaft,  gives 
the  rotary  motion  to  the  mandrels  (cathodes) ,  around  which 
the  copper  tubes  are  deposited;  the  same  gearing  also 
causes  the  backward  and  forward  traveling  of  the  bur- 
nisher frame. 

For  tubes  up  to  4  in.  inside  diameter  the  mandrels  are 
of  brass;  for  those  above  4  in.  inside  diameter  they  are 
of  cast  iron,  with  a  brass  neck  for  receiving  the  current. 
The  iron  mandrels,  previous  to  being  used  in  the  acid 
sulphate-depositing  tanks  for  the  production  of  copper 
tubes,  are  treated  in  an  alkaline  electrolytic  bath  contain- 
ing copper  anodes,  and  coated  with  a  thin  covering  of  cop- 
per. The  alkaline  bath  is  slightly  heated  in  order  to  forward 
the  depositing  action.  All  the  mandrels,  before  being 
placed  in  the  acid  sulphate-depositing  tanks,  are  carefully 
covered  with  black  lead,  to  facilitate  the  removal  of  the 
finished  tube. 

When  starting  work,  the  copper  anodes  are  placed  in 
the  tank  and  the  mandrels  are  nested  alongside  the  former, 
but  resting  at  both  ends  on  insulated  supports.  Acid  sul- 
phate is  then  led  into  the  tank  by  gravity  from  five  cylin- 
drical reservoirs  on  the  side  of  the  depositing  room ;  the 
positive  current  is  supplied  through  suitable  lead  conductors 
to  the  copper  anodes  and  the  negative  current  is  led  away 
from  the  mandrels  by  means  of  copper  conductors  and 
flexible  brushes.  The  mandrels  are  caused  to  revolve, 
while  agate  burnishers,  held  in  wood  supports  and  fitted 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  121 

to  a  frame  placed  transversely  over  the  tank,  are  made  to 
travel  automatically  up  and  down  the  whole  length  of  the 
tubes,  as  they  are  being  formed  by  deposition.  The  frame 
travels  on  paths  on  the  sides  of  the  tank,  and  is  driven, 
as  above  mentioned,  by  gearing  from  the  main  shaft.  The 
burnishing  gives  the  tubes  a  uniform  density  and  a  per- 
fectly smooth  surface,  it  is  claimed. 

The  works  can  manufacture  tubes  up  to  4  ft.  in  diam- 
eter and  13  ft.  in  length,  though  practically  there  is  no 
limit  to  the  size.  One  of  the  current  sizes  is  12  ft.  by  2^  in. 
outside  diameter,  and  about  No.  8  wire  guage  in  thick- 
ness. 

At  the  end  of  each  operation,  and  previous  to  removing 
the  mandrels  with  the  complete  tubes  from  the  tank,  a 
plug  is  raised  from  the  latter,  and  the  liquor  flows  by  gravi- 
tation to  three  cisterns  built  below  the  floor  level  of  the 
depositing  room,  and  in  which  the  sediment,  containing 
gold  and  silver,  has  time  to  settle.  These  cisterns  have  a 
capacity  of  12,360  cu.  ft.  The  liquor  is  pumped  up  from 
a  third  cistern  to  the  large  cylindrical  reservoirs  above 
referred  to,  where  it  is  treated  for  further  use  in  the  deposit- 
ing tanks. 

The  depositing  process  being  carried  out  with  nearly 
pure  copper,  poor  in  precious  metals,  the  sediment  in  the 
cisterns,  which  rarely  carries  as  much  as  6  oz.  of  gold  to 
the  ton  of  residue,  is  very  easily  handled. 

Four  of  the  bays  in  the  depositing  room  are  provided 
with  hand-lifting  gear ;  the  manufacture  of  larger  tubes 
and  the  copper  coating  of  heavy  rolls  are  carried  out  under 
the  fifth  and  sixth  bays,  which  are  provided  with  overhead 
electric  traveling  cranes,  each  of  5  tons  capacity. 

When  the  copper-coated  mandrels  are  removed  from 
the  depositing  tanks,  they  are  carried  to  an  adjoining 
machine-shop  and  placed  in  a  tube-expanding  machine, 
in  which  they  are  made  to  revolve  under  two  friction  rollers, 


J22  MODERN  ELECTROLYTIC  COPPER  REFINING. 

which  travel  along  the  whole  length  of  the  tube.  They 
are  then  placed  in  a  power  draw-bench  and  held  down. 
One  end  of  the  mandrel  is  fastened  to  a  grip,  and  the  latter, 
on  being  hooked  to  a  flat-link  chain  drawn  by  a  sprocket 
wheel,  removes  the  mandrel  from  the  inside  of  each  tube. 

This  shop  contains  tube-expanding  machines,  driven  by 
belt  transmission  from  an  overhead  shaft,  draw-benches 
driven  by  an  underground  shaft,  and  numerous  other 
tools,  such  as  power-hammers,  saws  for  cutting  the  tubes 
to  length,  and  lathes  for  turning  the  mandrels.  Overhead 
travelers  serve  all  the  bays  in  which  heavy  work  is  per- 
formed. 

Many  of  the  tubes  manufactured  are  drawn  in  the  draw- 
benches  through  dies,  in  order  to  give  them  the  required 
dimensions  to  meet  certain  specifications.  This  drawing 
has  the  effect  of  hardening  the  copper.  The  tubes  are  then 
placed  in  a  reverberatory  furnace,  in  which  they  are  heated 
to  a  low  red  heat,  after  which  they  are  quenched  in  water 
and  cleaned  in  acid  and  water  baths. 

The  machine-shop  contains  the  required  plant  for  test- 
ing the  tubes  by  hydraulic  pressure,  and  for  determining 
their  tensile  strength. 

Besides  the  tubes,  calico-drying  cylinders,  calico-print- 
ers' rolls,  paper-makers'  cylinders,  seamless  copper  cylin- 
ders for  hydraulic  machinery,  pump  liners,  and  hydraulic 
ram  covers  are  produced. 

The  copper  tubes  made  by  this  process  are  claimed  to 
be  able  to  stand,  without  showing  any  defects,  the  follow- 
ing mechanical  tests :  Doubling  close  cold  and  then  doubling 
over;  doubling  close  cold  and  opening  out;  creasing  up  on 
end,  expanding,  flanging  (diameter  across  the  flange  being 
equal  to  three  times  the  diameter  of  the  tube) ,  reducing  the 
doubled  edge  of  the  tube  to  a  knife-edge,  and  turning  back 
flat  in  its  hard  state,  without  breaking. 

The  Leeds  Copper  Co.  is  on  the  Admiralty  list  for  copper 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  123 

tubes  and  pipes  other  ttian  steam  pipes,  and  the  latter  are 
subject  to  the  British  Board  of  Trade  tests. 

A  plant  for  the  manufacture  of  drawn  brass  tubes  from 
the  copper  tube  scrap,  etc.,  is  now  being  erected  at  Huns- 
let,  Leeds.  The  output  of  this  new  plant  is  intended  to 
be  25  tons  per  week. 

The  Elmore  process  is  also  being  worked  by  the  Societe 
d'Electro-Metallurgie  de  Dives  at  Dives  in  France,  and 
by  the  Elmore  Metall  A.  G.  at  Schladern,  near  Cologne, 
Germany. 

5.  Vivian  Refinery. 

This  plant  forms  part  of  H.  H.  Vivian  &  Sons'  Copper 
Works,  it  appears,  and  must  not  be  confused  with  the 
Hafod  Copper,  Cobalt  and  Nickel  Works,  owned  by  H.  H. 
Vivian  &  Co.,  also  of  Swansea,  Wales.  The  refinery  has 
an  estimated  daily  output  of  8  to  10  tons  of  electrolytic 
copper. 

In  the  electrolytic  process  either  the  whole  of  the  coarse 
copper,  largely  received  in  the  shape  of  "regulus,"  is  refined 
direct,  or  else  auriferous  and  argentiferous  "bottoms"  are 
produced  by  fire  methods,  and  these  bottoms  are  then 
refined  electrolytically.  Various  makes  of  generators,  El- 
more's,  Gulcher's,  Crompton's  and  Edison-Hopkinson's, 
furnish  the  required  current. 

The  following  are  claimed  to  be  characteristic  features 
of  the  refining  methods  adopted:  The  anodes  are  cast 
shorter  and  narrower  in  size  than  the  cathodes,  in  order  to 
make  the  distance,  and  therefore  the  electrical  resistance 
between  the  edges  of  adjacent  electrodes  in  the  tanks  greater 
than  that  between  other  portions  of  these  plates,  and  thus 
lessen  the  current  density  at  the  edges  in  comparison  and 
check  the  tendency  of  the  copper  to  "tree"  across. 

By  setting  the  molds  a  little  out  of  the  level,  the  anodes 
are  cast  about  \  in.  thicker  at  the  top  than  at  the  bottom,. 


124  MODERN  ELECTROLYTIC  COPPER  REFINING. 

;so  as  to  check  the  tendency  of  the  anodes  to  be  eaten  away 
at  or  near  the  surface  of  the  electrolyte  and  diminish  the 
production  of  scrap  copper. 

In  stripping  the  cathode  sheets  from  their  copper  pat- 
tern plates,  the  latter  are  varnished  with  a  weak  shellac 
varnish  containing  about  i  Ib.  of  shellac  to  i  gal.  of  alcohol, 
which  prevents  the  deposited  copper  from  sticking  and  at 
the  same  time  is  not  sufficiently  thick  to  insulate  the 
cathodes  from  the  passage  of  the  current.  The  edges  of  the 
pattern  plates  are  dipped  in  "  Brunswick  black,"  and  the 
sheets  of  copper  are  then  easily  detachable  from  the  plates. 

The  voltages  in  the  tanks  are  preferably  tested  with  an 
ordinary  electric  bell,  especially  wound  so  as  to  ring  at  its 
ordinary  loudness  when  the  tanks  are  at  the  correct  volt- 
age. If  the  bell  rings  more  or  less  loudly,  it  is  a  sign  of 
either  dirty  contacts  or  of  short-circuiting  in  the  particular 
tank  under  test,  a  method  of  inspection  which  appeals  more 
to  the  average  Welsh  workman,  it  is  claimed,  than  reading 
a  delicately  pivoted  and  expensive  voltmeter. 

6.  McKechnie's  Refinery. 

This  plant,  a  part  of  McKechnie  Brothers'  Metal  Works 
at  Widnes,  produces  about  9  tons  of  electrolytic  copper 
daily.  It  is  believed  to  contain  234  depositing  tanks  and 
three  dynamos,  generating  1500  amperes  at  50  volts. 

C.  GERMANY. 
i.  Hamburg  Refinery. 

In  1895  the  estimated  production  of  the  North  German 
Refinery  at  Hamburg  was  1728  tons  of  electrolytic  copper 
annually  or  4.8  tons  per  diem;  at  present  the  output  is 
probably  nearly  10  tons  daily.  The  plant  was  started  in 
1876. 


DESCRIPTION  AND   VIEWS  OF  REFINING    WORKS.  125 

There  are  600  depositing  tanks  in  the  above  refinery, 
each  containing  a  large  number  of  very  narrow  cast  anodes. 
Its  able  manager,  Dr.  Emil  Wohlwill,  who  formerly  had 
considerable  trouble  in  his  two  plants  on  account  of  crystal- 
line growths  on  or  "sprouting"  of  his  cathodes,  has  now 
succeeded  in  almost  entirely  overcoming  this  difficulty  by 
interrupting  the  electrolytic  process  for  half  an  hour  daily 
and  arranging  that  the  electrolyte  contains  a  small  but 
sufficient  quantity  of  salt  or  chloride  in  addition. 

Schnabel  gives  a  table  in  his  "  Handbook  of  Metallurgy, " 
p.  266,  showing  that  with  each  I2-H.P.  Gramme  dynamo, 
delivering  a  current  of  300  amperes  at  27  volts  tension  to 
60  tanks,  the  Hamburg  refinery  deposits  1984  Ib.  of  copper 
in  24  hours.  The  effective  cathode  area  of  each  tank  is  nearly 
162  sq.  ft.,  a  current  density  of  1.85  amperes  per  sq.  ft.  is 
employed,  and  about  6.87  Ib.  of  refined  copper  are  deposited 
for  each  horse-power  hour. 

It  is  stated  that  the  anode  slimes  are  reduced  in  a  small 
blast-furnace  with  litharge  to  a  copper-lead  alloy,  and 
that  the  latter  is  then  cupelled  with  argentiferous  lead. 

The  Hamburg  refinery  is  certainly  the  largest  electro- 
lytic plant  in  Germany  and  probably  one  of  the  best 
arranged. 

2.  Mansfeld  Electrolytic  Copper  Works. 

The  product  of  this  plant,  operated  by  the  Mansfeld 
Kupferschiefer-bauende  Gewerkschaft  of  Eisleben,  is  esti- 
mated at  about  5  tons  of  electrolytic  copper  daily.  In 
1886  the  approximate  production  was  734  tons  annually 
or  2  tons  per  diem.  Wilde's  dynamos  are  employed  for 
generating  the  current,  which  is  distributed  among  the 
tanks  and  electrodes  by  the  ordinary  multiple  system. 

The  Mansfeld  Copper  Co.,  according  to  Kershaw,  estab- 
lished the  first  electrolytic  works  outside  of  England,  al- 
though Schnabel  claims  this  honor  for  the  Hamburg  re- 


126  MODERN  ELECTROLYTIC  COPPER  REFINING. 

finery,  and  started  their  small  refinery  at  Eisleben  in  1872, 
according  to  Kershaw,  and  in  1879,  according  to  Schnabel. 
The  anodes  consist  of  so-called  "bottom  copper,"  rich  in 
precious  metals,  obtained  from  roasted  raw  matte  by  the 
process  of  "extra  concentration  smelting."  The  latter 
process,  at  the  same  time,  produces  a  rich  slag,  which  is 
retreated,  and  an  extra  concentrated  matte,  which  runs 
about  78.2%  Cu,  0.47%  Ag,  0.38%  Pb,  0.48%  Fe,  0.01% 
Mn,  0.27%  Zn,  0.35%  Ni,  0.06%  Co,  and  19.68%  S, 
and  is  desilverized  by  the  Ziervogel  process  and  refined 
like  ordinary  concentrated  matte  to  a  refined  copper,  con- 
taining 99.75  to  99.8%  Cu  and  8  oz.  of  silver  per  ton. 
The  electrolytic  copper  produced,  being  free  from  silver,  is 
of  a  slightly  higher  grade  than  this  metal  and  of  greater 
conductivity. 

3.  Oker  Electrolytic  Refinery. 

This  plant,  operated  by  the  Koenigl.  u.  Herzogl.  Com- 
munion Huettenamt  at  Oker,  produces  about  5  tons  of 
electrolytic  copper  daily  with  water  and  steam  power,  rated 
at  100  H. P.  It  was  started  in  1878.  The  Oker  anodes  are 
39  in.  long,  20  in.  wide,  and  0.6  in.  thick.  The  cathode  pat- 
tern plates  are  made  of  electrolytic  copper  less  than  0.12  in. 
thick,  painted  over  with  petroleum  spirit  and  their  edges 
coated  with  paraffine. 

The  cathode-starting  sheets  are  suspended  from  the  con- 
ductors by  means  of  copper  strips  0.8  in.  wide  and  0.08  in. 
thick,  riveted  to  the  sheets  and  protected  where  immersed 
from  the  action  of  the  solution  by  a  coating  of  paraffine. 

According  to  Schnabel,  three  different  types  of  Siemens 
&  Halske  dynamos  are  employed  at  Oker,  varying  in  ten- 
sions from  3.5  to  30  volts,  according  to  the  number  of  tanks 
to  which  they  furnish  current,  and  in  current  strengths 
from  120  to  1000  amperes.  They  each  deliver  an  effective 
power  at  the  terminals  of  between  3500  and  4800  watts,  and 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  127 


each  deposit  between  551  and  66 1  Ib.  of  copper  in  24  hours. 
The  arrangement  of  electrodes  and  conductors  in  a  typical 


FIG.  64.— Lengths  Section  of  Electrolytic  Tank,  Oker  Refinery. 


FIG.  65. — Plan  View  of  Electrolytic  Tank,  Oker  Refinery, 
tank  is  shown  in  the  subjoined  cuts,  Figs.  64,  65,  and  66 
(from  Schnabel's  "Metallurgy). 


128 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


The  anode  slimes  are  treated  by  the  so-called  rich  bullion 
smelting  process  in  the  blast-furnace,  and  a  product  is 
obtained  consisting  of  rich  lead  bullion,  matte,  and  speiss. 


FIG.  66. — Cross-section  of  Electrolytic  Tank,  Oker  Refinery. 

This  lead  bullion  is  then  cupelled  and  parted  in  the  ordinary 
way  to  recover  the  precious  metals. 


4.  Goslar  Electrolytic  Refinery. 

This  plant,  belonging  to  Borchers  Bros.,  at  Goslar,  in  the 
Harz  Mountains,  produces  about  i  ton  of  electrolytic  copper 
daily,  it  is  reported.  About  1892  the  proprietors  of  the 
above  works  provided  their  electrolytic  tanks  with  a  novel 
apparatus,  claimed  to  have  been  invented  by  Werner  von 
Siemens  in  1884  or  1885,  for  effecting  the  circulation  of  the 
electrolyte.  Within  a  large  lead  pipe,  b,  which  is  open  at 
both  ends  and  which  connects  the  center  of  the  bottom  of 
the  electrolytic  bath  with  the  surface  of  the  liquid  at  one 
end  of  the  tank,  a  fine  jet  of  air  is  blown  into  the  liquid 
some  distance  from  the  surface  of  the  latter  by  means  of 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS. 


a  glass  tube,  g.  The  column  of  fluid  above  the  lower  end  of 
the  glass  tube  g,  mixed  with  small  air  bubbles,  grows  lighter 
in  sp.  g.  than  the  bulk  of  the  liquid  in  the  tank ;  it  therefore 
rises  and  flows  over  the  upper  end  of  the  pipe  6,  while  at 
the  lower  end  of  the  same  pipe  a  constant  current  of  heavy 
liquid  rushes  in.  An  almost  noiseless  but  very  lively  circu- 
lation is  the  result  of  this  process.  To  prevent  waste  o£ 


FIG.  67. — Siemens-Borchers  Copper-refining  Tank. 

liquid  by  ejecting  a  lead  cover,  d,  with  an  opening  toward 
the  electrodes,  must  be  placed  over  the  pipe  b.  c  =  collect- 
ing tray  for  anode  residues  and  slimes. 

The  above  apparatus  obviates  the  necessity  of  having 
the  electrode  flow  from  one  tank  to  the  next  of  a  long  series. 
The  impurities  of  one  tank  are  not  carried  through  the 
whole  line.  Each  bath  works  independently  of  the  rest. 
There  should  be  no  occasion  for  leakage  of  electric  current 


I30 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


and  wasteful  overflows  of  liquid,  as  in  the  old  system.  The 
electrolyte  remains  in  the  bath  from  the  start  up  to  the  time 
when  it  must  be  discarded.  The  liquid,  it  is  claimed,  will 
always  be  found  quite  clear,  a  very  important  point  in 
hunting  up  the  cause  for  any  troubles  in  the  line.  One  pipe 
line  only  is  required  to  fill  and  to  empty  the  tanks  by  air 
pressure  and  suction.  And  last,  but  not  least,  the  current 
density  may  be  raised  to  three  or  four  times  that  heretofore 
used  in  Europe.  This  means  nothing  less  than  the  possibility 
of  turning  out  three  or  four  times  as  much  copper  as  by  the 
old  method;  or  a  given  amount  of  metal  will  require  only 
-one-third  or  one-fourth  of  the  floor  space  formerly  needed. 
The  economy  of  operating  a  refinery  with  tanks  supplied 
with  the  above  apparatus,  as  compared  with  the  old  style 
of  tanks,  will  appear  from  the  following  table  furnished  by 
Siemens  &  Halske  for  technical  conditions  as  they  exist 
in  Germany: 


Daily  Operating  Cost  with  a  Production  of  i  Ton 
per  Diem. 

Formerly: 
Current  Density  3 
Amperes  per  sq.  ft. 

At  Present: 
Current  Density  10 
Amperes  persq.  ft. 

Cost  of  power  (  i  horse-power  hour  @  5  pfen- 

Mark  :  1  7  oo 

Mark  *  30  oo 

\Vages                   

'  '        ^o  oo 

'  '        15  oo 

Interest  on  copper  in  treatment  (5%)  
Amortization     of     the    electrical    installa- 
tion do%)      

15.60 
"          8  .  ^o 

4.80 
4    IS 

'Cost  of  heating  the    electrolyte    (250    kg. 
coal)                                   •       

(  C 

1  '           ^  oo 

•Cost  of  regenerating  the  solution 

'  '          4  oo 

Mark:  74.90 
=  $17.60 

Mark:  58.95 
=  $13-85 

5.  Schladern  Electrolytic  Works. 

The  Elmore  Metall-Actiengesellschaft,  whose  head  office 
is  in  London,  is  operating  a  modified  Elmore  process  at 
Schladern  a.  d.  Sieg,  near  Cologne,  Germany.  The  process 
:and  equipment  employed  being  identical,  it  is  claimed, 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  131 

with  that  of  the  Leeds  Copper  Works,  excepting  in  size, 
I  must  refer  the  reader  to  the  description  of  the  latter 
plant  on  pages  116  to  123  of  this  monograph.  About  1000 
H.P.  are  employed  in  these  works  and  somewhat  better 
results  have  been  secured,  it  is  claimed,  than  in  England. 

6.  Niedermarsberg  Refinery. 

This  refinery,  also  known  as  the  Stadtberger  Huette, 
at  Niedermarsberg,  near  Cologne,  is  operated  in  connection 
with  a  leaching  plant.  Carbonate  ores  containing  about 
2%  Cu  are  leached  with  a  solution  of  hydrochloric  acid 
and  salt  and  with  such  iron  chloride  solutions  as  are  ob- 
tained in  a  subsequent  stage  of  the  extraction  process. 
In  this  way  about  1.5%  Cu  is  recovered,  while  the  greater 
part  of  the  remaining  0.5%  Cu  in  the  ore  is  extracted  from 
the  dump  of  the  leached  ore  as  follows:  The  floor  of  the 
dump  pile  is  located  on  a  level  above  that  of  the  leaching 
plant,  so  that  the  cupriferous  solutions  resulting  from  the 
action  of  the  residual  chloride  solutions  in  the  leached  ore, 
together  with  that  of  the  oxygen  and  moisture  of  the  atmos- 
phere on  the  ore,  may  be  washed  down  by  rain-water  into 
ditches  and  their  copper  contents  precipitated  therein  by 
scrap  iron.  In  this  way  a  very  high  extraction  of  the  copper 
contents  of  the  ore  is  effected  and  nearly  900  tons  of  metallic 
copper  are  recovered  annually. 

The  precipitation  of  the  copper  is  carried  out  in  such  a 
way  as  to  first  throw  down  practically  all  of  the  precious 
metals  in  the  solution,  together  with  about  37%  of  its 
copper  contents  only,  thus  obtaining  a  product  which  is 
sent  to  the  electrolytic  refinery  (arranged  on  the  old  Siemens 
pattern)  for  separation,  while  the  greater  portion  of  the 
copper  in  the  cupriferous  solutions  is  thrown  down  by 
means  of  scrap  iron  free  from  precious  metals,  and  there- 
fore merely  requires  furnace  refining  to  put  it  into  market- 
able shape. 


132  MODERN  ELECTROLYTIC  COPPER  REFINING. 

The  total  copper  output  of  the  Stadtberger  Huette  is 
nearly  900  tons  annually,  of  which  about  330  tons  rep- 
resents electrolytic  copper. 

7.  Altenau  Electrolytic  Works. 

This  plant,  operated  by  the  Koenigliches  Huettenamt 
Altenau  im  Oberharz,  receives  power  furnished  by  a  Brie- 
gleb  Hausen  turbine,  delivering  between  17  and  28  H.P., 
according  to  the  available  quantity  of  water.  In  reserve 
is  kept  a  20  H.P.  horizontal  condensing  engine,  working 
with  8  atmospheres  boiler  pressure. 

The  daily  production  of  electrolytic  copper  is  at  present 
from  0.8  to  i  ton. 

The  anode  slimes  are  mixed  with  lime,  pressed  into 
.bricks,  dried,  and  smelted  in  a  blast-furnace  with  a  lead 
charge  and  basic  slags,  and  the  argentiferous  lead  bullion 
thereby  obtained  is  cupelled  and  parted  in  the  ordinary 
way. 

8.  Burbach  Refinery. 

This  plant,  belonging  to  Mr.  C.  Schreiber,  of  Burbach 
Siegen,  is  a  very  small  one,  operated  with  but  15  H.P.  and 
producing  not  over  0.2  ton  of  electrolytic  copper  daily  by 
the  ordinary  multiple  process. 

9.  Papenburg  Electrolytic  Works. 

These  works,  belonging  to  the  Allgemeine  Elektro- 
Metallurgische  Gesellschaft,  at  Papenburg  an  der  Ems,  are 
said  to  be  producing  a  small  output  of  copper  and  nickel, 
according  to  a  modified  Hoepfner  process,  using  a  chloride 
solution.  It  is  stated  that  the  capacity  for  which  the  works 
were  designed  is  as  much  as  i  ton  of  refined  copper  daily, 
although  the  actual  output  is  only  a  fraction  of  a  ton,  and 
that  the  following  process  is  in  use:  The  ores  and  matte 


DESCRIPTION  4ND   VIEWS  OF  REFINING   WORKS.  133 

received  at  the  works  are  leached  with  a  cupric  chloride 
solution,  so  as  to  dissolve  their  copper,  nickel,  and  silver 
contents  and  simultaneously  reduce  the  cupric  salt  to  the 
cuprous  state.  After  purification  and  being  freed  from 
silver,  the  solution  is  passed  into  electrolytic  cells  with 
carbon  anodes  and  copper  cathodes.  Chlorine  is  liberated 
at  the  anodes,  and  the  cupric  solution  remaining  after 
electrolysis  is  withdrawn  and  reused  in  leaching  a  fresh 
charge  of  ore  or  matte  until  it  is  found  desirable  to  recover 
the  nickel  in  the  solution. 

Very  recent  reports  indicate  that  the  Papenburg  con- 
cern has  not  achieved  as  successful  results  as  were  ex- 
pected, and  that  the  entire  plant  is  therefore  being  re- 
modeled. 

D.  AUSTRIA-HUNGARY. 

By  VICTOR  ENGELHARDT. 
i.  Witkowitz  Electrolytic  Refinery. 

This  plant,  owned  by  the  Bergbau  u.  Eisenhuettenge- 
werkschaft  at  Witkowitz,  Moravia,  was  started  eighteen 
years  ago  in  connection  with  the  treatment  of  pyrites  cin- 
ders from  the  acid  works,  which  were  then  and  are  now 
used  in  part  in  making  pig  iron,  owing  t6  the  difficulty 
of  obtaining  iron  ores  from  other  sources  low  enough  in 
phosphorus  to  fall  within  the  Bessemer  limit  for  steel. 

The  aforesaid  pyrites  cinders  contain,  besides  a  few 
tenths  of  a  per  cent,  of  copper,  larger  proportions  of  residual 
sulphur.  Both  of  these  elements  are  converted  into  solu- 
ble compounds  by  giving  the  cinders  a  chloridizing  roast 
and  then  leaching  them,  whereby  a  residue  is  obtained 
which  is  used  in  making  iron.  The  copper  in  the  leach 
liquor  is  precipitated  with  iron  as  cement-copper  finally, 
which  product  contains  Cu,  Fe,  Pb,  As,  Ag,  and  traces 
of  Au,  and  is  refined  electrolytically.  Electrolytic  refining 


T34  MODERN  ELECTROLYTIC  COPPER  REFINING. 

was  adopted  for  the  reasons,  i,  that  it  enabled  the  separa- 
tion of  the  copper  from  the  other  metals  to  be  effected 
easily  and  completely;  2,  because  the  copper  was  obtained 
as  a  readily  salable  product,  and  3,  because  a  large  differ- 
ence in  prices  existed  between  electrolytic  and  fire-refined 
copper  at  the  time  the  works  were  built. 

The  cement-copper  is  first  partially  refined  by  a  reduc- 
ing smelting  process  and  then  cast  into  anodes.  The 
original  cathodes  are  thin  sheets  of  copper  suspended 
between  anodes  in  the  electrolyte,  which  contains  35  to 
40  g.  Cu  as  copper  sulphate  and  50  to  55  g.  SO3  per  liter 
of  solution. 

The  composition  of  the  anodes  is  as  follows:  94-98% 
Cu,  0.4-1%  Ag,  0.2-1%  O,  0.02-0.7%  Fe,  0.8%  As,  0.05% 
Pb,  and  traces  of  S,  Ni,  Co,  and  Au. 

At  the  commencement  of  operations,  in  1884,  the  plant 
contained  two  rows  of  6  tanks  each,  with  8  anodes  and  7 
cathodes  to  a  tank.  A  Siemens  machine  of  240  amperes 
and  ii  volts  furnished  the  required  current,  which  was 
employed  at  a  current  density  of  only  25  amperes  per 
square  meter,  equivalent  to  2.5  amperes  per  square  foot  of 
cathode  surface. 

At  present  there  are  72  tanks  in  use,  the  adjoining 
tanks  of  a  pair  being  separated  by  a  partition  which  allows 
free  communication  of  their  solutions  below.  A  tank  holds 
but  4  anodes  and  3  cathodes. 

The  current  is  furnished  by  two  Siemens  &  Halske 
generators,  one  cF7  of  240  amperes  and  n  volts,  and  the 
other  cH7  of  300  amperes  and  17  volts.  An  average  cur- 
rent of  290  amperes  is  used,  and  a  current  density  of  66 
amperes  per  square  meter  of  surface,  i.e.,  6.6  amperes  per 
square  foot. 

The  average  annual  output  of  the  plant  is  92.5  metric 
tons  of  copper,  analyzing  99.99%  Cu.  It  is  reported  that 
in  one  year  2231  metric  cwt.  of  electrolytic  copper  were 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS.  135 

produced  from   3260   metric   cwt.    of  cement-copper,   ob- 
tained from  470,600  metric  cwt.  of  pyrites  cinders. 

2.  Brixlegg  Electrolytic  Refinery. 

This  plant  at  Brixlegg,  Tyrol,  belongs  to  the  K.  K.  Berg 
u.  Huettenverwaltung,  and  contains  60  depositing  tanks, 
1 2  electrolytic  receiving  tanks,  6  membrane  pumps  for 
raising  the  circulating  solution,  2  ampere-meters,  3  volt- 
meters, 2  torsion-galvanometers,  and  2  Siemens  &  Halske 
generators,  type  cH7,  with  .air  commutators,  and  delivering 
a  current  of  240  amperes  at  20  volts  potential. 

In  1884  the  government  installed  the  first  p^ant,  con- 
sisting of  i  generator  and  2  rows  of  10  tanks  each, 
arranged  in  cascades,  and  with  a  receiving  tank  and  pump 
for  each  row.  To  this  plant  additions  were  made  from 
time  to  time,  so  that  at  present  there  are  two  dynamos 
in  use,  one  serving  4  rows  of  10  tanks  each  and  the  other 
2  rows. 

The  material  treated  in  the  electrolytic  refinery  consists 
of  gold-  and  silver-bearing  partly  refined  black  copper  con- 
taining only  90%  Cu  and  i%  Ag,  besides  0.005%  Au. 
The  electrolyte  is  an  acid  solution  of  bluestone.  The 
electrolytic  cathodes  produced  are  remelted  in  a  refining 
furnace  and  cast  into  cakes  for  rolling  into  sheet,  and  the 
silver  slimes  are  refined  by  cupellation  with  lead  on  a 
cupel  hearth. 

The  average  annual  output  of  the  refinery  amounts  to 
45  to  47.5  metric  tons  of  copper. 

E.  FRANCE. 
i.  Dives  Electrolytic  Works. 

These  works  are  operated  by  the  Societe  d'Electro- 
Metallurgie  de  Dives,  Paris,  which  is  allied  to  the  Leeds 
Copper  Works,  Ltd.,  and  is  using  a  modified  Elmore 


136  MODERN  ELECTROLYTIC  COPPER  REFINING. 

process   of  depositing  copper  for  tubes,  etc.,  rather  than 
a  refining  process  proper. 

The  plant,  located  at  Dives,  Normandy,  has  been  run- 
ning for  some  years  past  and  constituted  the  pattern 
after  which  the  Leeds  Copper  Works  have  been  built  and 
equipped.  The  reader  is,  therefore,  referred  to  the  de- 
tailed description  of  that  plant  on  pages  116  to  123. 

2.  Biache  St.  Vaast  Electrolytic  Works. 

These  works,  belonging  to  the  Societe  Anonyme  des 
Fonderies  et  Laminoirs  de  Biache  St.  Vaast  (formerly 
Eschger,  Chesquiere  et  Cie),  with  offices  in  Paris,  in  1895 
had  an  estimated  output  of  about  780  tons  of  electrolytic 
copper.  The  company  at  present  declines  to  give  out  any 
information. 

Dr.  C.  Schnabel's  table,  referred  to  above,  shows  that 
with  each  8-H.P.  Gramme  dynamo,  delivering  a  current  of 
700  amperes  at  4  volts  tension  to  20  tanks,  the  Biache 
refinery  at  Pas  de  Calais  deposits  nearly  882  Ib.  of  copper 
in  24  hours.  The  effective  cathode  area  of  each  tank  is  a 
little  over  227  sq.  ft.,  a  current  density  of  about  3  amperes 
per  square  foot  is  employed  and  about  4.6  Ib.  of  refined 
copper  are  deposited  for  each  horse-power  hour. 

The  anode  slimes  are  reduced  in  a  blast-furnace  with 
litharge  to  a  copper-lead  alloy,  and  the  latter  is  then 
cupelled  with  argentiferous  lead. 

3.  Pont  de  Cheruy  Refinery. 

This  plant,  also  known  as  the  Grammont  Affinerie, 
located  at  Pont  de  Cheruy,  in  1895  had  an  annual  output, 
it  is  claimed,  of  about  400  tons  of  electrolytic  copper.  The 
tanks  are  connected  in  series  and  the  electrodes  in  parallel. 

The  anode  residue,  containing,  say,  25%  Cu  and  i%  to 
6%  Ag,  is  treated,  according  to  Thofehrn,  by  exposing  it 


DESCRIPTION  AMD   VIEWS  OF  REFINING   WORKS.  137 

to  the  atmosphere  and  then  melting  it  down  to  get  rid  of 
the  greater  part  of  its  metallic  oxides  other  than  those  of 
copper  and  silver.  For  this  purpose  a  magnesia  brick-lined 
refining  furnace  is  used.  Finally  an  alloy  containing  as 
much  as  80%  Cu  and  15%  Ag  is  produced,  which  is  cast 
into  plates  and  subjected  to  electrolysis  in  special  vats,  in 
which  the  main  refinery  current  and  electrolyte  is  caused 
to  circulate.  Merchantable  copper  is  thus  obtained  and 
slimes  rich  enough  in  silver  for  final  acid  treatment  in  the 
usual  way. 

4.  Marseilles  Electrolytic  Refinery. 

This  plant,  belonging  to  Hilarion,  Roux  et  Cie,  Mar- 
seilles, according  to  Schnabel,  in  1898  produced  about  551 
Ib.  of  copper  daily  with  a  5-H.P.  Gramme  dynamo,  deliver- 
ing 300  amperes  at  8  volts  tension  to  40  tanks.  The  effect- 
ive cathode  area  of  each  tank  is  about  242  sq.  ft.,  the  current 
density  employed  about  1.24  amperes  per  sq.  ft.,  and  4.59 
Ibs.  of  refined  copper  are  deposited  per  hour  for  each  horse- 
power used. 

The  Societe  de  Cuivre  de  France's  Refinery  at  Eguille, 
whose  annual  output  in  1895  was  reported  at  noo  tons 
and  whose  general  arrangement  was  planned  by  H.  Tho- 
fehrn,  is  not  now  in  operation. 

F.  RUSSIA. 

I.  Kalakent  Copper  Works. 

By  GUSTAV  KOELLB. 

These  works  (owned  by  the  Hon.  Carl  H.  von  Siemens 
and  the  heirs  of  the  late  Privy  Councillor  Werner  von 
Siemens)  were  established  for  the  purpose  of  electrolytically 
refining  crude  copper  and  securing  the  contained  precious 
metals,  and  are  located  at  Kalakent,  near  the  Kedabeg 
Copper  Works,  about  60  wersts  or  40  miles  southwest  of 


138 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


the  city  of  Elisabethpol  and  42  wersts  or  28  miles  from 
Dalliar  Station  on  the  Transcaucasian  Railroad. 

Originally  the  plant  was  intended  to  carry  out  experi- 
ments on  a  large  scale  for  the  direct  electrolytic  extraction 
of  copper  from  ores,  according  to  the  well-known  Siemens, 
and  Halske  sulphate  process,  but  it  was  remodelled,  as  far 
back  as  1889,  and  operated,  at  first  with  36  tanks,  in  pro- 


10         5          0  30  iO  fathoms 

FIG.  68.— Ground  Plan  of  Kalakent  Works. 

ducing  merchantable  copper  from  black  copper  anodes 
containing  not  over  90%  Cu,  and  from  which  anode  re- 
sidues, running  at  most  2  %  in  silver  and  gold,  were  secured. 
As  the  working  up  of  these  residues  occasioned  difficulty, 
and  moreover,  as  the  obtained  electrolytic  copper  was  of 
an  uncertain  quality,  this  non-paying  procedure  was  given 
up,  and  in  its  stead  the  management  substituted  the 
refining  of  blister  copper  instead  of  black  copper  and 
increased  the  plant  in  size.  As  such  the  works  were  operated 


DESCRIPTION  AMD   VIEWS   OF  REFINING    WORKS. 


139 


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XTesting  Boom 


140  MODERN  ELECTROLYTIC  COPPER  REFINING. 

continuously  from  1893  up  to  1900,  since  which  time  they 
have  been  closed  down,  because  it  was  believed  that  no 
profit  could  be  realized  by  them  on  account  of  the  follow- 
ing facts:  i.  The  small  percentage  of  precious  metals  (on 
an  average  only  0.06%),  and  of  which  the  gold  amounts 
to  but  -fa  to  -fa  part,  in  the  Kedabeg  copper;  2,  the  small 
margin  of  profit  between  electrolytic  and  fire-refined  copper, 
which  was  reduced  to  only  25  kopeks  per  pud,  i.e.,  o.3c. 
per  Ib. ;  and  finally,  the  abnormally  high  local  prices  of 
certain  necessary  supplies,  such  as  sulphuric  acid,  which  cost 
1.90  rubel  per  pud,  i.e.,  2.7C.  per  Ib.  The  electrolytic  copper- 
refining  industry  in  Kalakent  is  therefore  dormant  at  the 
present  time. 

The  Kalakent  works  embraced  102  electrolytic  tanks, 
and  were  designed  for  an  annual  output  of  25,000  pud,  or 
450  tons,  of  fine  copper. 

Current  was  obtained  from  Siemens  &  Halske  shunt- 
wound  dynamos  furnishing  700  amperes  at  35  volts,  and 
of  which  only  one  machine  was  kept  in  operation  at  a  time. 

The  tanks  were  arranged  in  four  rows,  all  placed  on  the 
same  level.  The  arrangement  of  the  tanks,  as  indicated 
in  Figs.  70  and  71,  differed  from  the  ordinary  and  usual 
disposition,  particularly  with  respect  to  the  system  of 
circulating  and  renewing  the  electrolyte.  It  permitted  of 
making  each  tank  an  independent  unit,  if  desired,  by  the 
employment  of  Siemens  air-lifts,  two  of  which  were  placed 
in  each  tank  to  circulate  the  electrolyte.  This  made  pos- 
sible the  operation  of  the  tanks  individually  or  grouped  in 
any  desired  way  and  number,  facilitated  the  control  of  each 
tank,  and  permitted  the  easy  renewal  or  restandardizing 
sectionally  of  impure  or  abnormal  solutions,  which  is  a  very 
important  consideration. 

The  tanks  were  built  of  pine,  2  m.  or  6.6  ft.  long,  1.15 
m.  or  3.8  ft.  high,  and  0.96  m.  or  3.1  ft.  wide,  inside  meas- 
urements, and  were  lined  with  jute  linen  soaked  in  asphalt, 


DESCRIPTION  AND   VIEWS  OF  REFINING    WORKS. 


141 


-Asphalt 


142  MODERN  ELECTROLYTIC  COPPER  REFINING. 

a  method  not  to  be  specially  recommended,  but  which  was 
in  this  case  employed  because  the  price  of  lead  in  Russia  is 
exceptionally  high.  It  possesses  this  disadvantage,  that  the 
jute  lining  is  apt  to  be  ripped  open  by  falling  sharp-edged 
pieces  of  copper,  which  is,  of  course,  partly  provided  against 
by  placing  wooden  boards  on  the  bottoms  of  the  tanks. 
Another  difficulty  arises  from  the  quality  and  treatment 
of  the  calking  material,  in  this  case  Welsh  asphalt  and 
asphalt  varnish,  for  if  this  material  is  not  boiled  sufficiently 
long  before  using,  it  will  be  acted  upon  by  the  free  acid  in 
the  tank  and  cause  an  evolution  of  oxygen  and  carbonic 
acid,  which  in  turn  may  injuriously  oxidize  the  cathode 
copper.  Its  advantage  over  lead  lining  lies  only  in  its 
cheapness,  and  possibly  also  in  the  lesser  liability  therewith 
of  having  short  circuits. 

The  conductors,  electrolytic  copper  bars  placed  length- 
wise of  the  tanks,  were  500  sq.  mm.  or  1.7  sq.  in.  in  cross- 
section,  or  not  quite  as  large  in  sectional  area  as  the  main 
conductors.  Each  tank  contained  15  anodes  and  14  cathode 
plates,  so  that  it  had  an  anode  at  each  end.  The  electrodes 
were  arranged,  as  usual,  in  parallel,  and  the  tanks  in  series 
circuit.  The  electrodes  were  spaced  about  5  to  6  cm.  or 
about  2  in.  apart.  It  was  observed  that  if  this  distance 
was  decreased  there  arose  danger  of  short-circuiting,  and 
if  increased,  the  voltage  became  too  great  for  economy. 

The  effective  anode  area  per  tank  was  20  sq.  meters 
or  200  sq.  ft.;  of  the  cathodes,  19  sq.  meters  or  about  190 
sq.  ft. 

Every  anode,  cast  from  ordinary  blister  copper,  weighed 
between  8  and  10  pud.,  i.e.,  about  248  to  360  lb.,  and 
was  about  90  cm.  or  about  3  ft.  long,  86  cm.  or  2.8  ft. 
wide,  and  2  cm.  to  2.5  cm.  or  .8  in.  to  i  in.  in  thick- 
ness. Serving  as  cathodes  to  receive  the  commercially  de- 
posited copper  in  the  tanks  were  employed  sheets  of  electro- 
lytic copper  2  mm.  or  .08  in.  thick,  obtained  in  the  usual 


DESCRIPTION  AND   VIEWS  OF  REFINING   WORKS. 


143 


way  in  special  cathode  tanks  by  electro-deposition  on  plates 
of  ordinary  rolled  copper  smeared  with  oil  and  graphite, 
and  whose  edges  were  insulated  with  paraffine.  Before 
using  they  were  first  freed  from  adhering  oil,  etc.,  by  heating, 


FIG.  72. — Details  of  Cathode  Connections. 

and  were  then  supplied  with  the  necessary  suspending  and 
conducting  strips. 

To  accomplish  the  circulation  of  the  electrolyte,  which 
had  to  be  carried  on  with  the  greatest  energy  to  secure 
good,  even  copper  deposits,  each  tank  was  supplied  with 
two  geyser  pumps  (air-lifts)  whose  construction  is  clearly 
indicated  in  Fig.  73.  By  means  of  air  pressure  admitted 
through  the  narrow  pipe,  shown  in  the  figure,  continu- 
ously under  a  pressure  of  70  mm.  or  2.8  in.  mercury  column, 
the  solution  from  near  the  bottom  of  the  tank  is  lifted  up 
through  the  larger  pipe  and  overflows  into  a  distributing 
trough  above  the  tank  to  mix  with  or  renew  the  layer  of 
electrolyte  near  the  top.  In  this  way  about  800  liters  of 
solution  are  circulated  per  tank  and  hour. 

Current  densities  of  25  amperes  up  to  a  maximum  of 
30  amperes  per  square  meter  or  3  amperes  per  square  foot 
of  cathode  area  were  employed;  an  increase  of  the  am- 
perage above  this  maximum  resulted  in  brittleness  of  the 
deposited  copper  unless  the  acidity  of  the  electrolyte  was 


144 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


increased  simultaneously.  A  remarkably  high  average 
current  efficiency,  99%,  was  obtained  in  the  Kalakent 
works.  In  order  to  secure  a  very  good  deposit  of  fine 


FIG.  73. — Circulation  Pump  (Air-lift). 

copper,  it  was  found  that  the  acidity  had  to  be  kept  at  not 
less  than  70,  and  generally  between  75  and  85  grams  of 
free  sulphuric  acid  per  liter,  and  that  at  least  36  grams  of 
copper  had  to  be  present  in  a  liter  of  solution. 

The  composition  of  the  better  brands  of  fire-refined 


DESCRIPTION  AND  YIEWS  OF  REFINING   WORKS.  145 

blister  copper  used  as  Anodes  was  as  follows:  99.57%  Cu, 
0.06%  to  0.08%  Ag+Au,  0.027%  Pb,  0.038%  As,  0.060% 
Sb,  0.031%  Ni  +  Co,  0.009%  Fe,  and  traces  of  bismuth. 

Notwithstanding  the  comparatively  low  contents  in 
impurities  of  the  material  treated,  these  accumulated  in 
the  course  of  time  and  then  necessitated  purification  of 
the  electrolyte  to  prevent  deterioration  of  the  copper 
deposits.  Especially  dangerous  was  the  concentration  in 
the  solution  of  those  oxides  easily  soluble  in  dilute  acid, 
such  as  iron  and  arsenic  (arsenious  acid)  and  also  of  bis- 
muth and  antimony  compounds.  As  long  as  a  sufficient 
excess  of  copper  over  these  other  metals  was  present  in 
the  electrolyte,  and  the  total  amount  of  these  impurities 
did  not  exceed  a  certain  maximum,  indicated  by  the  pecul- 
iar appearance  of  the  cathode  surfaces,  no  fault  could  be 
found  with  the  deposited  copper.  The  presence  of  an 
abundance  of  free  sulphuric  acid  in  the  bath  prevented 
the  precipitation  of  the  oxides  of  copper  at  the  negative 
poles. 

When  the  impurities  in  the  electrolyte  had  accumulated 
to  such  an  extent  as  to  endanger  the  quality  of  the  elec- 
trolytic copper,  the  foul  solutions  were  withdrawn  from 
the  individual  tanks  or  tank  groups  and  regenerated,  this 
regeneration  being  accomplished  with  considerable  diffi- 
culty at  first,  but  finally  it  was  done  advantageously  as 
follows : 

The  foul  solutions  were  heated  and  passed  over  dead- 
roasted  matte  fines  heaped  in  loose-bottomed  trays  arranged 
in  series  in  upright  rows.  By  this  method  all  the  sulphuric 
acid  in  the  solution,  down  to  about  2  grams  per  100  cu.  cm., 
was  neutralized  and  combined  with  copper  and  iron.  The 
solution  was  then  allowed  to  trickle  through  heaps  of 
roasted  low-grade  copper  ores,  which  resulted  in  the  almost 
complete  neutralization  of  its  acid  contents.  It  was  now 
diluted  with  wash  waters  down  to  10°  to  12°  B.  and  heated, 


146  MODERN  ELECTROLYTIC  COPPER  REFINING. 

to  free  the  solution  from  iron,  arsenic,  tin,  and  bismuth, 
in  lead  pans,  which  were  provided  with  an  appliance  for 
injecting  compressed  air  into  the  solution.  Anode  scrap 
was  suspended  in  the  pans  so  as  to  neutralize  any  remain- 
ing  portions  of  acid,  and  to  take  up  any  new  acid  set  free 
through  separation  of  iron  hydrates,  and  thereby  form 
copper  sulphate.  By  blowing  compressed  air  into  the 
solution  heated  to  about  50°  C.,  the  copper  in  the  anode 
residues  or  scrap  was  quickly  dissolved,  and  the  separation 
of  the  iron,  arsenic,  antimony,  tin,  and  bismuth,  which 
occurred  when  the  solution  had  been  nearly  or  completely 
neutralized,  accomplished.  The  solution  was  then  con- 
centrated up  to  14°  to  15°  B.  and  clarified  in  special  reser- 
voirs. It  now  contained  3.5  to  4  grams  copper  per  100 
cu.  cm.,  and  of  impurities  only  0.5  to  i  gram  iron,  besides 
traces  of  zinc,  nickel,  and  cobalt,  and  was  therefore  pure 
enough  for  reuse  as  electrolyte.  The  excess  of  purified  elec- 
trolyte which  gradually  accumulated  with  this  method  of 
regeneration  was  eventually  withdrawn  from  the  circulat- 
ing system  and  worked  up  into  bluest  one. 

The  electrolytic  copper  put  on  the  market  possessed  a 
purity  of  at  least  99.9%  by  analysis  and  averaged  99.93% 
copper.  It  was  sold  in  the  shape  of  plates  weighing  8  to  9 
pud  (i.e.  288  to  324  lb.). 

The  silver  mud  or  anode  slimes  obtained  as  a  by- 
product in  refining  the  anode  copper  were  not  worked  up 
into  gold  and  silver  bullion,  but  were  merely  enriched  and 
shipped  to  Germany  and  sold,  this  being  considered  a 
more  profitable  procedure  than  their  treatment  in  Russia. 

The  enrichment  of  the  slimes,  consisting  chiefly  in  the 
partial  removal  of  the  contained  copper,  was  carried  out  as 
follows : 

After  removing  any  adhering  solution  from  the  mud  by 
washing  with  water  and  decantation,  the  slimes  were 
leached  with  a  quantity  of  impure  acid  electrolytic  solu- 


DESCRIPTION  AND  VIEWS  OF  REFINING  WORKS.          147 

tion,  heated  to  from  50°  to  55°  C.,  so  as  to  diminish 
their  copper  contents  from  35%  or  40%  down  to  10%  or 
15%  Cu.  The  leached  slimes,  which  were  then  sold,  aver- 
aged 25%  to  30%  in  precious  metals,  of  which  gold  con- 
stituted the  fourteenth  to  seventeenth  part.  Practically 
all  of  this  material  was  purchased  by  the  North  German 
Refinery  in  Hamburg. 

2.  Nikolajev  Refinery. 

This  electrolytic  plant  at  Nijni  Novgorod,  comprising 
70  depositing  tanks,  a  few  years  ago  was  producing  at  the 
rate  of  15,000  puds  of  electrolytic  copper  per  year,  which 
equals  about  0.75  ton  per  day.  A  current  density  of  45 
amperes  per  square  meter  of  cathode  surface,  equivalent  to 
4.5  amperes  per  square  foot,  is  reported  as  being  employed 
in  refining  the  crude  copper  treated. 


CHAPTER  III. 

COST  ESTIMATES  OF  AN  AMERICAN  COPPER  AND  NICKEL 
REFINERY,  WITH  GENERAL  PLAN  AND  DETAIL  DRAW- 
'    INGS. 

Description  and  Specifications. — The  following  preliminary 
estimates  and  plans  refer  to  proposed  custom  refining  works 
to  be  located  at  Sault  Ste.  Marie,  Michigan,  where  cheap 
water-power  is  available,  and  arranged  in  accordance  with 
my  improved  copper-nickel  refining  process  and  plant.  I 
designed  the  works  for  a  daily  productive  capacity  of  75 
tons  of  fine  copper,  7.5  tons  of  fine  nickel,  and  for  refining 
the  precious  metals  contained  in  the  material  to  be  treated. 

The  chief  data  for  the  estimates  were  obtained  by  se- 
curing bids  for  the  items  specified,  and  were  carefully  com- 
piled. 

The  works  are  designed  especially  for  treating  anodes 
of  crude  nickeliferous  copper,  averaging,  say,  88%  Cu, 
8.8%  Ni,  and  22.13  oz.  of  Ag  per  ton,  valued  at  approxi- 
mately II.SG.  and  isc.  per  Ib.  for  the  contained  copper 
and  nickel  respectively,  and  not  exceeding  5oc.  per  oz.  for 
the  contained  silver,  or  a  total  of  about  $239.87  per  ton. 

These  nickeliferous  copper  anodes  may  be  secured  by 
bessemerizing  charges  of  Sudbury  copper-nickel  matte  added 
to  common  argentiferous  copper  matte  and  pouring  the 
converted  metal  into  the  desired  shape,  or  by  adding  Sud- 
bury matte  to  argentiferous  copper  concentrates,  such  as 
silver-bearing  " mineral"  from  the  Quincy,  Isle  Royale, 
Osceola,  and  other  Upper  Peninsula  stamp-mills,  to  bring 

148 


BALANCE  TABL 


OFFICE  g 

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L 

(V 

OFFICE 

TESTING 
ROOU 



ASSAY 
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SILVER 
REFINERY 


CRYSTALIZING    NICKEL  REFINERY  AND 
HOUSE  SEPARATING  HOUSE 


TANK  HOUSE 


- 


PLAN 
FIG.   74. — Plan,  Elevation,  and  Section  of 


FURNACE  BUILDING 


Proposed  Copper  and  Nickel  Refinery. 


[To  face  page  148.] 


SEC! 


-647- 


PL 
FIG.   75. — Plan  and  Sect  on  of  Proposec 


ci  Copper  and  Nickel  Refinery. 


[To  face  page  149.] 


COST  ESTIMATES  OF  A  REFINERY,  WITH  PLANS,  ETC.     149 

up  the  quantity  of  contained  copper  to  nine  or  ten  times 
the  quantity  of  nickel  present,  refining  this  charge  and 
pouring  the  finished  alloy  into  anodes. 

The  required  power,  between  3400  and  4000  H.P.,  is  to 
be  furnished  in  the  shape  of  a  3 -phase  alternating  current 
of  10,300  volts,  delivered  to  the  high-tension  switchboard 
of  the  refinery  power-house,  at  a  total  yearly  cost  or  price 
of  $12.50  per  metered  electrical  horse-power  at  the  generat- 
ing station. 

The  works  are  to  be  located  on  a  site  having  facilities 
for  shipping  both  by  rail  and  water,  flat  in  topography  and 
•at,  least  12  acres  in  extent.  They  are  designed  with  a  view 
to  permitting  of  future  extensions  in  at  least  two  directions 
by  a  simple  duplication  of  existing  sections.  Furthermore, 
the  arrangement  shown  in  the  attached  plan  drawings,  Figs. 
74  and  75,  will  permit  of  erecting  a  limited  section  of  the 
works,  with  whatever  output  of  refined  copper,  nickel,  and 
precious  metals  may  be  decided  upon  at  first. 

The  cost  of  whatever  coal  may  be  used  in  the  remelting 
and  refining  furnaces,  in  excess  of  that  figured  on  in  the 
operating  cost  of  the  electrolytic  process,  is  considered  as  a 
•direct  charge  upon  the  cost  of  manufacturing  the  copper, 
nickel,  and  precious  metals  into  ingots,  plates,  slabs,  and 
wire  bars.  The  selling  price  is  assumed  at  1 2  ct.  per  Ib.  for 
the  copper,  24  ct.  per  Ib.  for  the  nickel,  and  50  ct.  per  oz. 
for  the  silver.  In  case  of  any  increase  or  decrease  in  the 
quoted  prices  of  the  metals  refined,  after  purchase,  the 
total  profits  of  refining  would,  of  course,  be  proportion- 
ately increased  or  decreased. 


150  MODERN  ELECTROLYTIC  COPPER  REFINING. 

SUMMARY. 
Item.  Estimated  Cost. 

Land $1,200 

Grading  land  and  building  dock 32,000 

Tracks 5,040 

Office  building 13,058 

Power-house 68, 100 

Tank-house 161,610 

Furnace  building 143,800 

Separating  house  and  nickel  refinery. .     34,540 

Crystallizing  house 20,300 

Silver  refinery 27,380 


Total  cost  of  plant $507,028 

Permanent  stock  on  hand 1,296,296 

Incidentals,     contingencies,     and     sinking 

fund 196,676 


Permanent  capital  invested $2,000,000 


Value  of  total  yearly  output. $8,046,000 

Yearly  operating  cost $116,280 

Price  of  metal  stock  purchased 

annually 7,625,051 

Freight  charges  to  market. .  .  .        148,600 


Total  expenses 7,625,051 


Total  annual  profit 420,949 


Percentage  of  profit  on  capitalization 21.05% 


Pitch  on  all  Trusses  =  1/g 


-Runway  Reams  24" 

10  Ton  Crane 


-500 


c 

SOY 


spaced  4'OW  F">»r  U— «*»  per  3q.f,. 


Steel  PurHiis  on  all  Buildings,  consisting  of  5"  I  Beams  9%'#  and  5"channel 

Roof  surfaces  of  Buildings  A  and  E  covered  with  corrugated  iron,  painted  with  3  coats  of  Graphite  Paint. 

Sides  and  Ends  of  Building  E  covered  with  corrugated  iron,  painted  with  3  coats  of  Graphite  Paint,  attached 

Floors  on  this  building  onry. 


\] 

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9 

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B 

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No  floor  req'd 

No  floor  req'd 

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Sleel  Girts. 


Trusses  supported  on  Columns  throughout  with  curtain  walls  between  Columns,  exceptin 
and  prable  ends  instead  of  brick  curtain  walls. 

FIG.  76. — Diagram  showing  General  Construction  of  Proposed  Co] 


X^xfc^  ^<3^t/^   1    ^\^fc>*^ 

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Kane                     10  Ton  Crane 
III 

Run  way  Ifori 
10  Ton  Cifane! 



1  :  —  6o'«^-: 

Truss 

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1?K1 

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—  Rafter  Beam  carrying  Roof,  Truss  omitted 
Charging  Floor,  Concentrated  Load  at 
any  point  =  4000  * 

**ty*£^ 

^ 

-Truss 

Truss 

\ 

—  Truss,  etc. 

I 

(                        E 

Assumed  Load  on  Trusses  =  40"  per  horizon  t 

Side  Pressure  on  E  =  30  *  per-vejrtica] 

Maximum  Wheel  Loads  for  Cranes  = 

> 

60000*  on  2  wheels  9V  C.  to  C. 

:; 

C 

C 

f 

-. 

1 

which  has  corrugated  iron  sidines 

nd  Nickel  Refinery  as  submitted  by  the  Canadian  Bridge  Co 


[To  face  page  150.] 


r— i 


1 1  20"  x  05* 


16  g''><    16  S^^- 


2ND  AND  3RD  FLOOR   PLAN 
[< 3rd  Floor 

I a 


-2nd  Floor- 


F 


500- 


I 


11 


CRYSTALI2  NQ  AND  SEPAR 
AND  SILVER  Ml 


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\/ 


-150 


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co 


Truss 


s 

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03  '0- 


BOTTOM  LATERAL  BRACING 


ROOF  PLAN  BOTTOM  LATERAL  BRACIN 

7 7. —Floor  and  Roof  Plan  of  Buildings  for  the  Proposed  Cor 


R 

3-^ 

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7 


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FANK  HOUSE 


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BOTTOM 
LATERAL  BRACING 


ROOF  PLAN 


ROOF  PLAN 

ind  Nickel  Refinery.     Submitted  by  the  American  Bridge  Co. 


[To  face  page  151.] 


'""T' 


;-'•-.;     •     '  f .          ,    t  •  •    t      i   .    v  *• 

£4:U-!.v-  !;WXJ-U 


UTT : 
—••  -':F' 


COST  ESTIMATES  OF  A  REFINERY,  WITH  PLANS,  ETC.      15* 
GENERAL    EXPENDITURES. 

(1)  Lana,  12  acres  @  $100  per  acre $1,200 

( Actual  area  required,  allowing  yard  room 
for  doubling  the  capacity  of  the  plant,  836  X 
647  ft.) 

(2)  Grading  land  and  building  dock. 32,000 

(Excavations  to  cost  not  exceeding  $1.00  per 
cu.  yd.,  and  masonry  $6.50  per  cu.  yd.  Dock 
to  be  400  ft.  long  by  20  ft.  wide.) 

(3)  Tracks,  168  tons  @  $30.00  per  ton 5,040 

(Industrial  road,  to  be  3o-in.  gauge  and  rails 
20  Ib.  per  yd.) 

OFFICE    BUILDING. 
(50  ft.  by  60  ft.,  two  stories.)     See  Fig.  74. 

Foundations $1,850 

Brick 4,408 

Woodwork i  ,200 

Furnishings 2,100 

Fittings 1,500 

Laboratory  equipment 2,000 


$13,058 

POWER-HOUSE. 
(50  ft.  by  66  ft.,  one  story.)     See  Figs.  74  and  82. 

Foundations $2,000 

Brick 4,800- 

,  Woodwork 1,200 

Furnishings 2,100 

Fittings 1,500 

Switchboards  and  instruments 5,ooo 

Three   step-down   transformers 12,000 

Three  rotary  converters 39,5oo 

$68,100 


152  MODERN  ELECTROLYTIC  COPPER  REFINING. 

TANK-HOUSE. 
(189  ft.  by  304  ft.,  one  story.)     See  Figs.  74,  75,  77,  78,  79,  80,  and  81. 

Excavations  and  foundations $7,500 

Brick,  240  M.  @  $25.00  per  M.,  laid 6,000 

Woodwork  and  furnishings,  including  50  windows.  1,000 

Fittings,  including  workbenches  and  8  doors 1,000 

Steel  columns,  trusses,  and  runways 60,000 

Roofing,  580  sqs.  @  $7.00  per  sq 4,060 

Pumps  and  accessories 4,000 

Air-compressor 1,700 

Lead  for  lining  tanks 21,700 

Copper  conductors  and  incidentals 6,000 

Lead  burning 4,050 

Tanks  (woodwork) 7,5°° 

Lumber  for  floors  and  platforms 4,000 

Brick  foundations  for  tanks 7,000 

Concrete  flooring 2,500 

Trolleys 2,000 

Pipes  for  steam  heating,  etc 1,500 

Three  lo-ton  anode-handling  cranes 20,100 


$161,610 

FURNACE    BUILDING. 

(336  ft.  by  in  ft.,  one  and  one-half  story.)     See  Figs.  74,  76,  77.  and  82. 

foundations $7,500 

•Steel  columns,  trusses,  and  runways,  corrugated 

iron  roofs  and  sidings 45,000 

One  lo-ton  traveling  crane 3,600 

Furnishings  and  fittings 1,000 

:Six  5o-ton  reverberating  furnaces,  with  flues, 

complete 42,000 

One  loo-ton  blast  furnace  and  accessories 6,000 

Six  Walker  casting-machines,  with  water-boshes, 

complete 2  7 ,000 

One  Wellman-Seaver  charging  machine 9,000 

'Six  72-foot  stacks 2,700 


$143,800 


ir 


^2  Anchor  Bolts  l"0 


CROSS  SECTION  B-B 


-16  0 

SIDE   ELEVATION 


— 160- 

SECTION  E-E 


FIG.   78. — Drawing  showing  Steel  < 


HOUSE 

t*l  on  Roof. 

"    Gables. 

Ridge  Caps. 
*    Gutters. 


END  ELEVATION 


Construction  of  the  Tank-house. 


[To  face  page  152.] 


/Tx 


, 


FIG.  79. — Sketch  showing 


r  3 


-- 


•££ 


Arrangement  of  Tanks. 


[To  face  page  153.] 


CO57  ESTIMATES  OF  A  REFINERY,  WITH  PLANS,  ETC.     153 


154 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


FIG.  81. — Clearance  Sketch  of  Charging  Machine. 

SEPARATING-HOUSE    AND    NICKEL    REFINERY. 

(128  ft   by  50  ft.,  two  stories.)     See  Figs.  74,  76,  77,  83,  84,  85,  and  86 

Foundations • $3>7°° 

Brick 4,4oo 

Woodwork 2,400 

Furnishings 2,  TOO 

Fittings i,5°o 

Sixty-eight  nickel-depositing  tanks  and  conductors .  .  2,720 

Steel  columns  and  trusses 9-320 

Johns  asbestos  roofing 680 

Two  separators 2,000 

Two  sulphite  converters 800 

Two  concentrators 4°° 

Two  purifiers 5°° 

Two  sludge  receivers,  generators,  etc i,oco 

Six  supply  tanks 420 

Two  large  and  eight  small  receiving  tanks 800 

One  air-compressor  and  receiver 1,100 

One  electric  motor 7°° 

$34,540 


«-  %v)  X^i-^^        "?  y^yx^ly  ^  «iM**ij>fcHj-pM<jiu 

filtul 


*®®WW$SSQIIW^ 

CROSS  SECTION  C-C  FURNACE  BUILDING 


Q 


Fici.  82. — Drawing  showing  Stee.  Construction 


10  ELEVATION 


o 


30,000 
HGRAM 
5TRIC  CRANE 


SECTION  F-F 


-30- 


Tr 


POWER  HOUSE 


the  Furnace  Building  and  Power-house. 


[To  face  page  154.] 


SILVER   MILL 

CROSS  SECTION  A-A 


CRYSTAL 


FIG.  86. — Sketch  showing  Steel  Construction  of  the  Silvc 


.IZING 


SEPARATING   HOUSE 
END  ELEVATION 


1  C  6'x  8*     * 


160 

SIDE  ELEVATION 

cr  Mill  and  the  Crystallizing  and  Separating-house. 


160" 


SECTION  D-D 


[To  face  page  155.] 


COST  ESTIMATES  OF  A  REFINERY,  WITH  PLANS,  ETC.     155 


FIG.  83. — Separating-house.     Cross-section. 
DESCRIPTION    OF   APPARATUS. 

At  separator  for  precipitating  copper  sulphide. 

B,  converter  for  making  copper  sulphate. 

C,  concentrator  for  removing  hydric  sulphide. 

D,  purifier  for  removing  iron  and  arsenic. 

E,  sludge  receiver. 

Ft  generator  for  producing  hydric  sulphide. 

<7,  supply  tanks  for  sulphuric  acid. 

H,  receiving  tanks  for  the  acid  electrolyte. 

/,  supply  tanks  for  hot  water. 

/,  receiving  tanks  for  copper  solution. 

K,  receiving  tanks  for  nickel  solution. 

Lt  supply  tanks  for  ammonia. 

M,  air  receiver. 

JV,  tracks. 

0,  motor  for  driving  machinery. 

P,  air  compressor. 

fifl',  cross-section  of  separating-house. 

77',  longitudinal  section. 


MODERN  ELECTROLYTIC  COPPER  REFINING. 


COS7  ESTIMATES  OF  A  REFINERY,  WITH  PLANS,  ETC.     157 


158  MODERN  ELECTROLYTIC  COPPER  REFINING. 

CRYSTALLIZING-HOUSE. 
(128  ft.  by  50  ft.,  three  stories.)     See  Figs.  74,  76,  77,  and  86. 

Foundations $3,700- 

Brick 2,100 

Woodwork ••*•!•( •• 2,400 

Furnishings  and  fittings 1,500 

Steel  columns  and  trusses 7,320 

Johns  asbestos  roofing. . !.  J  .\  .  ..; 680 

Two  oxidizing  tanks 200 

Two  settling  tanks 100 

Four  boiling  tanks 600 

Twenty  crystallizing  tanks 1,600 

One  screen  and  dryer i  oo 


$20,300 


SILVER    REFINERY. 
(128  ft.  by  50  ft.,  one  story.)     See  Figs.  74,  76,  77,  and  86. 

foundations $3, 700 

Brick 2,100 

Woodwork 2,400 

Furnishings  and  fittings 1,500 

Steel  columns  and  trusses,  corrugated  iron  roof..  .  8,000 

Electrolytic  parting  plant 4,000 

Three  parting  kettles  and  accessories 1,200 

One  slime-refining  furnace 1,200 

One  silver  cupelling  furnace 800 

Sjix  boiling  and  settling  tanks 480 

ifryers,  screens,  tools,  etc 2,000 

$27,380 


COS7  ESTIMATES  OF  A  REFINERY,  WITH  PLANS,  ETC.     159 


OPERATING    COSTS    AND    ANTICIPATED    PROFITS. 

(Based  on  a  daily  output  of  75  tons  of  fine  copper,  7.5  tons  of  fine  nickel,  and 
1500  oz.  of  silver  =  85. 227  tons  of  anodes  treated  daily.) 

Assets. 

Plant $507,028 

Stock  of  anodes  in  treatment,  2557 

tons  @  $239.87  per  ton $613,348 

One  month's  stock  on  hand  of  an- 
odes, 2557  tons  @  $239.87  per 
ton 613,348 

Copper  in  conductors,  40  tons  @  $250 

per  ton 10,000 

Copper  in  solution,  200  tons  @  $230 

per  ton 46,000 

Nickel  in  solution,  20  tons  @  $680 

per  ton 13,600 


Permanent  stock  on  hand 1,296,296 

Incidentals,     contingencies,      and     sinking 

fund 196,676 


Permanent  capital  invested $2,000,000 


Liabilities. 

Cost  of  refining  copper  per  ton : 

Labor $0.75 

Current 1.50 

Supplies,  acid,  coal,  etc 67 

Lighting 08 

$3-00 
Refining  charge 6.00 


Profit  per  ton  of  copper $3.00 


160  MODERN  ELECTROLYTIC  COPPER  REFINING. 

Cost  of  separating  and  refining  nickel  per  ton: 

Labor $0.75 

Current 6.00 

Supplies,  acid,  coal,  etc. .  .      7.17 
Lighting 08 

$14.00 
Royalty,     with    separating 

and  refining  charge...  .200.00 


Profit  per  ton  of  nickel $186 

Yearly  Operating  Cost  : 

Copper:  27,000  tons  @  $3 $81,000 

Nickel:  2,700  tons  ©$14 35,280     $116,280 


Price  of  metal  stock  purchased  annually,  30,684 

tons  @  $239.87  per  ton 7,360,171 

Freight  charges   to    market,    29,720  tons    @  $5 

per  ton 148,600 


Total  expenses $7,625,051 

Value  of  Total  Yearly  Output  : 

Copper:  27,000  tons  @  $240 $6,480,000 

Nickel:  2,700  tons  @  $480 1,296,000 

Silver:  540,000  oz.  @  5oc 270,000 

—  $8,046,000 

Total  expenses  .Y 7,625,051 


Total  annual  profit $420,949 


Percentage  of  profit  on  capitalization 21. 05% 


APPENDIX. 


CHRONOLOGICAL    LIST    OF    PATENTS,    BOOKS,   AND 
SPECIAL  ARTICLES  ON  ELECTROLYTIC  COPPER- 
REFINING  METHODS  AND  APPARATUS. 

1865.  Copper  Refining,  English  Pat.  No.  2,838  of  Nov.  3;  James 
Elkington. 

1869.  Copper  Refining,  English  Pat.  No.  3,120  of  Oct.  27;  James 

Elkington. 

1870.  Copper  Refining,  U.  S.  Pat.  No.  100,131  of  Feb.  22;  James 

Elkington. 

1883.  "Electrolysis  in  the  Metallurgy  of  Copper,  Lead,  Zinc  and  other 

Metals"  by  C.  O.  Mailloux.     Mineral  Resources  of  the 
U.  S.,  Washington,  pp.  627-658. 

1884.  "Data  on  the  Oker  Refinery,"  by  H.  Froelich.     Elektrotechn. 

Zeitschrift,  p.  466  et  seq.     Berlin. 

1885.  4< Behavior  of  Constituents  of  Blister  Copper  in  Electrolytic  Re- 

fining," by  M.  Kiliani.     Berg-  u.  Huetten-Zeitg. ,  p.  249. 
Berlin. 

Method  of  Arranging  Plates  in  Copper  Refining,  U.  S.  Pat. 
No.  322,170  of  July  14;  Moses  G.  Farmer,  New  York. 

1886.  "Electro-Deposition  of  Gold,  Silver,  Copper  and  other  Metals," 

by  A.  Watt,  London. 

Refining  Process,  German  Pat.  No.  42,243  of  Sept.  14;  Sie- 
mens &  Halske. 

Method  of  Using  Endless  Cathodes  in  Copper  Refining,  U.  S. 
Pat.  No.  355,905,  Feb.  9;  Moses  G.  Farmer,  New  York. 

ilEinfiuss  der  Stromdichte  auf  die  Festigkeit  des  Kathoden- 
niederschlags,"  by  H.  Hubl  Mitth.  des  K.  u.  K.  militar- 
geogr.  Instituts,  6,  p.  51. 

161 


1 62  APPENDIX. 

1888.  Copper  Refining,  German  Pat.  No.  53,782  of  March  i;   Carl 

Hoepfner. 

Copper  Refining,  U.  S.  Pat.  No.  393,526  of  Nov.  27 ;  H.  Smith. 

"Grundriss  der  Elektrometallurgie,"  by  C.  A.  Balling,  Stutt- 
gart, Germany. 

1889.  Refining  Process,  German  Pat.  No.  48,959  of  Jan.  3;  Siemens 

&  Halske. 

1890.  "The  Electrolytic  Separation  of  Metals,''  by  G.  Gore,  London. 

1891.  "The  Electro-Deposition  of  Metals,"  by  G.  Gore,  London. 
"The  Art  of  Electro-Metallurgy,"  by  G.  Gore,  London. 
Copper  Refining  Apparatus,  U.  S.  Pat.  No.  465,525  of  Dec.  22  ; 

H.  Hayden. 

1892.  "L' Electrolyse,"  by  H.  Fontaine.    Baudry  et  Cie,  Paris. 
"Thofehrn's  Electrolytic  Refining  Process,"  by  H.  Fontaine. 

The  Mineral  Industry,  Vol.  I,  p.  163. 

"A  Treatise  on  Electro-Metallurgy,"  by  W.  G.  McMillan,  Lon- 
don. 

Arrangement  of  Electrodes,  U.  S.  Pats.  Nos.  467,350  and 
467,484  of  Jan.  19;  Otto  Stalmann. 

"Practical  Notes  on  the  Electrolytic  Refining  of  Copper"  by 
Lieut.  F.  B.  Badt.  Proc.  Am.  Inst.  Elect.  Eng'rs,  June  8. 
Chicago,  111. 

1893.  "Thofehrn  Process  of  Purifying  Solutions,"  Berg-  u.  Huetten- 

Zeitg.,  Bd.  LII,  p.  53,  nach  Revue  Industrielle  fuer  1892, 
No.  24  et  seq.,  by  Carl  Hering. 

"American  Practice  in  Electrolytic  Copper  Refining"  by  Titus 
Ulke.  The  Mineral  Industry,  Vol.  II,  pp.  273-286. 

"Thofehrn's  Improved  Electrolytic  Process  "  by  Hippolyte  Fon- 
taine. The  Mineral  Industry,  Vol.  II,  p.  282.  New  York^ 

1894.  "Handbuch  der  Metallhuettenkunde,"  Bd.  I  and  II,  by  Carl 

Schnabel.    Springer,  Berlin. 
"Zur    Elektrolytischen    Gewinnung     von    Kupfer     nach    dem 

Hoepfnerschen  Verfahren,"  by  E.  Jensch.     Chem.  Zeitg., 

p.  1906.    Berlin. 
"Progress  in  Electrolytic  Refining  of  Copper  during  1893,"  ^7 

T.  Ulke.    The  Mineral  Industry,  Vol.  III.    New  York. 
Arrangement  of  Electrodes,  U.  S.  Pat.  No.  514,275  of  Feb.  6;. 

T.  Randolph. 

1895.  ('Data  on  the  Marches^  Process   at  Stolberg,"  by  E.  Cohen. 

Zts.  Elektrochemie,  Jahrg.  II,  S.  25. 

"Progress  in  Electrolytic  Refining  of  Copper  during  1894,"  by 
T.  Ulke.  The  Mineral  Industry,  Vol.  IV,  New  York. 


APPENDIX.  163 

1895.  Car  and  Set  of  Molds  for  Casting  Anodes  Direct  from  Con- 

verters, U.   S.   Pat.  No.  539,270,  May  14;  H.  Hixon  and 
J.  A.  Dyblie. 

"The  Electrolytic  Refining  of  Copper,"  by  M.  Barnett.  Peters' 
Modern  Copper  Smelting,  pp.  576-606.  New  York. 

1896.  "Elektro-Metallurgie,"  by  W.  Borchers.      Braunschweig,  pp. 

166-217. 
"The  Progress   of  Electrochemistry  and  Electrometallurgy  in 

1895,"  by  W.  Borchers.     The  Mineral  Industry,  Vol.  IV, 

pp.  806-808. 
"Improvements  in  the  Electrolytic  Refining  of  Copper"  by  T. 

Ulke.     Engineering  and  Mining  Journal,   Nov.  14.     New 

York. 
Apparatus  for  Electrolytic  Circulation,  U.  S.  Pat.  No.  563,093 

of  June  30;  A.  E.  Schneider  and  Oscar  Szontagh. 
"Present  Method  of  Treating  Slimes  from  the  Copper  Refineries" 

by  T.  Ulke.  The  Engineering  and  Mining  Journal,  Nov.  28. 
"The  Anaconda  Refinery"  The  Engineering  and  Mining  Jour- 
nal, Sept.  19,  pp.  271-273.   New  York. 
"Progress  in  the  Electrolytic  Refining  of  Copper  "  by  T.  Ulke. 

The  Mineral  Industry,  Vol.  V,  p.  89.    New  York. 

1897.  "Electric  Smelting  and  Refining"  by  W.  Borchers  and  Walter 

G.  McMillan.     London. 

"Copper  Refining"  by  J.  B.  C.  Kershaw.  The  Electrician, 
London,  Jan.  8,  pp.,  337,  338. 

"Tank  Residues  in  Electrolytic  Copper  Refineries"  by  Ed- 
ward Keller.  Journal  Am.  Chem.  Soc.,  XIX,  No.  10. 

"Copper  Refining"  by  John  B.  C.  Kershaw.  The  Electrician, 
Jan.  1 8,  pp.  385,  386.  London. 

"Electric  Copper  Refining  in  the  United  States"  by  T.  Ulke. 
Cassier's  Magazine,  Sept.  New  York. 

1898.  "Progress  in  Electrolytic  Copper  Refining  in  1897,"   by  T. 

Ulke.    The  Mineral  Industry.  Vol.  VI,  pp.  238-244.     New 

York. 
"Handbook  of  Metallurgy"  by  Carl  Schnabel.    Translated  by 

Henry  Louis,  London.    Vol.  I,  pp.  260-274. 
"Die  Verarbeitung  des  Elektrolyten  in  Amerikanischen  Kupfer- 

werken"  by  T.  Ulke.    Zts.  f.  Elektrochemie,  4,  309. 

1899.  Method  of  Producing  Electrolytic  Copper  Wirebars,  U.  S.  Pat. 

No.  638,917  of  Dec.  12;  Elisha  Emerson,  Providence,  R.I. 
Method  of  Electrolytically  Refining  Copper,  U.  S.  Pat.  No. 
617,886;  Elisha  A.  Smith,  Anaconda,  Mont. 


1 64  APPENDIX. 

1899.  "The  Electrolysis  and  Refining  of  Copper,"  by  Edward  Keller. 

The  Mineral  Industry,  Vol.  VII,  pp.  229-260.    New  York. 

"Einfiuss  der  Temper  atur  des  Elektrolyten  in  der  Kupf  err  agina- 
tion" by  Foerster  and  Seidel.  Zts.  f.  Elektrochemie,  5,  508. 

Mold  for  Casting  Anodes,  U.  S.  Pat.  No.  631,471  of  Aug.  22; 
J.  T.  Morrow,  Great  Falls,  Mont. 

1900.  "Treatment  of  Silver  Slimes  in  Electrolytic  Copper  Refining" 

by  J.  C.  Roberts.    Colorado  School  of  Mines  Quarterly  for 
May.     Golden,  Col. 

"Progress  in  the  Electrolytic  Refining  of  Copper  during  1899," 
by  T.  Ulke.  The  Mineral  Industry,  Vol.  VIII,  pp.  184- 
188,  New  York. 

1901.  "The  Present  Status  of  the  Electrolytic  Refining  Industry  in  the 

United  States,"  by  T.  Ulke.     Electrical  Review,  Jan.   12, 

p.  85.     New  York. 
Plant   for    the   Electrodeposition   of   Metals,    U.   S.   Pat.-  No. 

687,800  of  Dec.  3;  Arthur  L.  Walker,  Perth  Amboy,  N.  J. 
"The  Raritan  Copper  Works"  by  Lawrence  Addicks.     The 

Mineral  Industry,  Vol.  IX,  pp.  261-276.     New  York. 
"Progress  in  the  Electrolytic  Refining  of  Argentiferous  Copper," 

by  T.  Ulke.     The  Mineral  Industry,  Vol.  IX,  pp.  223-234. 

New  York. 
Rapidly  Rotating  Mandrels,   British   Pat.    No.  9,731;   S.  O. 

Cowper-Coles. 
Improved  Form  of  Cathode  Plate,  U.  S.  Pat.  No.  683,263  of 

Oct.  12 ;  E.  G.  Elliott  and  V.  Kishner,  Perth  Amboy,  N.  J. 
Improved  Form  of  Cathode  Plate,  U.  S.  Pat.  No.  684,291 ;  W. 

A.  McCoy,  Perth  Amboy,  N.  J. 

1902.  Metallurgical  Crane,  U.  S.  Pat.  No.  697,788  of  April  15 ;  David 

W.  Blair. 
"Electrolytic  Process  of  Recovering  Copper,"  by  N.  S.  Keith. 

Electrical  Review,  Vol.  40,  No.  12,  of  March  22.    New  York. 
Art  of  Refining  Composite  Metals,  U.  S.  Pat.  No.  694,699  of 

March  4;  T.  Ulke,  Sault  Ste.  Marie,  Ont. 
"Progress  in  the  Electrolytic  Refining  of  Copper  in  1901,"  by 

T.   Ulke.      The  Mineral  Industry,  Vol.   X,  pp.   217-228. 

New  York. 
1  Treatment  of  Slimes  from  the  Electrolytic  Refining  of  Copper" 

by  Robert  L.  Whitehead.     The  Mineral  Industry,  Vol.  X, 

pp.  229-230.    New  York. 
"Corrosion  in  Depositing  Copper"  by  H.  Sayer  and  F.  S.  Spiers. 

Electrochemist  and  Metallurgist,  April,  p.  103.     London. 


APPENDIX.  165 

1902.  "Progress  in  the  Making  of  Elite  Vitriol,"  by  O.  Hofmann.    The 

Mineral  Industry,  Vol.  X,  pp.  231-242.     New  York. 
"Electrochemical  Polarization,"  by  C.  J.  Reed.   Journal  of  the 

Franklin  Institute,  April.    Philadelphia,  Pa. 
"Elektro-Metallurgie,"  3.  Auflage,  by  W.  Borchers,  pp.  182- 

268  incl.     Braunschweig,  Germany. 
"Electro-Plating  and  Electro-Refining  of  Metals,"  by  Arnold 

Philip.    Being  a  revision  of  Watt's  "  Electro-Deposition." 

London. 
"The  Electrolytic  Dissolution  of  Soluble  Metallic  Anodes, "by 

Woolsey  McA.  Johnson.     Trans.  Am.  Electrochem.  Soc.t 

Vol.  II,  pp.  171-173.     Philadelphia. 


INDEX. 


PAGE 

Altenau  Electrolytic  Works 132 

American  Electrolytic  Copper  Refinery,  Design  of 148-160 

Cost  Estimates  of 150-160 

Crystallizing  House,  Cost  of 158 

Description  and  Specifications 148 

Furnace  Building,  Cost  of 152 

General  Expenditures 151 

Office  Building,  Cost  of 151 

Operating  Costs  and  Profit , 159 

Operating,  Estimate  of  Costs  of 150 

Plant,  Estimate  of  Costs  of. ...    « 150 

Power  House,  Cost  of , 15 1 

Separating  House  and  Nickel  Refinery,  Cost  of. 154 

Silver  Refinery,  Cost  of 158 

Stock,  Estimate  of  Costs  of. 150 

Tank  House,  Cost  of 152 

Anaconda  Electrolytic  Copper  Refinery 89-99 

Anodes,  Casting  of 76,  77,  89,  96,  101 

Anodes,  Molds  for  Casting  of. 104,  109 

Anodes,  Shapes  of 85 ,  101,  104 

Assaying  of  Copper  Material 16 

Balbach  Refinery 107-1 10 

Baltimore  Copper  Works 100-102 

Biache  Refinery 136 

Blast-furnace  Building,  Raritan  Works 79 

Blue  Island  Refinery 113 

Bluestone,  Making  of. 24-46 

Bolton's  Froghall  Refining  Works 113,  114 

Bolton's  Widnes  Refinery 115 

Books  on  Electrolytic  Copper  Refining 161-165 

167 


1 68  INDEX. 

PAGE 

Brixlegg  Refinery 135 

Buffalo  Refinery in,  112 

Burbach  Refinery 132 

Casting  Machines 89,  90,  101 

Chemistry  and  Physics  of  Refining 17-26 

Chronological  List  of  Literature  on  Refining 161-165 

Comparison  of  Methods 7-13 

Copper,  Testing  of 60,  61,  112 

Cost  Estimates  of  Typical  American  Refinery 148-160 

Cost  of  a  30-ton  Refinery 87 

Cost  of  Producing  Electrolytic  Copper 3 

Data,  Historical I 

Data,  Statistical $2-55 

Definitions  and  General  Principles 3-6 

De  Lamar  Refining  Works no 

Descriptions  of  Refining  Works 56-147 

Detail  Drawings  of  Typical  Refinery I53~I57 

Development  of  Electrolytic  Copper  Refining 1,2 

Dives  Electrolytic  Works : 135 

Efficiency  of  Plants 14 

Electrolytic  Copper,  Cost  of  Producing 3 

Electrolytic  Copper  Refineries,  Descriptions  of 56-147 

Electrolytic  Copper  Refineries,  Outputs  of. 52 

Electrolytic  Copper  Refineries,  Plans  and  Views  of 58-101 

Electrolytic  Copper  Refining,  Development  of. I,  2 

Electrolytic  Copper  Refining,  Literature  of. 161-165 

Electrolytic  Copper  Refining,  Methods  and  Apparatus  of 7~5* 

Froghall  Refinery :•••*»  •• XI3 

Furnace  Building,  Cost  of. 152 

General  Expenditures  for  Grading  Land,  etc 151 

General  Expenditures  for  Land,  Tracks,  etc 15  r 

General  Plans  of  Typical  American  Refinery 148-152 

Goslar  Refinery 128 

Great  Falls  Refinery 103-106 

Guggenheim  Refinery 80-88 

Hamburg  Refinery •••;•, I2 

Hayden  System,  Discussion  of  . . . . I7~3>  100-102 

Historical  Data I,  2 


INDEX.  169 


Kalakent  Copper  Works 13? 

Leeds  Copper  Works 116-122 

List  of  Patents,  Books  and  Special  Articles 161-165 

Making  Bluestone 27-46 

Mansfeld  Copper  Works 125 

Marseilles  Electrolytic  Works 137 

McKechnie's  Refinery 124 

Metal  Stock  Required  in  Refining 14,  15 

Methods,  Comparison  of 7-!3 

Modern  Practice,  Resume  of 51 

Multiple  System,  Discussion  of 7-13 

Nichols  Refinery 99 

Nickel  Refinery,  Cost  of 154 

Niedermarsberg  Refinery 131 

Nikolajev  Refinery 147 

Office  Building,  Cost  of 151 

Oker  Refinery 126 

Operating  Costs  and  Profits 159 

Outputs  of  Electrolytic  Works 52~55 

Papenburg  Electrolytic  Works 132 

Patents,  List  of.    161-165 

Pembrey  Copper  Works 1 15 

Perth  Amboy  Plant 80-88 

Pont  de  Cheruy  Refinery 136 

Power  House,  Cost  of 15 1 

Raritan  Copper  Works 56 

Refining,  Chemistry  and  Physics  of 17-26 

Refining  Methods 7-I3 

Refining,  Stock  of  Metal  Required  in 14 

Refining  Works,  Descriptions  and  Views  of 56-147 

Resum£  of  Modern  Practice 5X 

Sampling  and  Assaying 16 

Schladern  Electrolytic  Works 130 

Separating  House,  Cost  of 154 

Series  System,  Discussion  of 7-13,  99-102 

Shapes  of  Wire  Bars   Cakes  and  Slabs 8l,  82 

Silver  Refinery,  Cost  of 158 

Slimes,  Treatment  of. 47~5O 


i 70  INDEX. 

PAGK 

Special  Articles  on  Refining 161-165 

Stock  of  Metal  in  Refining 14 

Sulphate  Building,  Raritan  Works 79 

Tables  giving  Outputs,  etc.,  of  Copper  Refineries 52~55 

Tank  House,  Cost  of 152 

Tank  House,  Plans  and  Details  of 148-153 

Treatment  of  Slimes 47~5° 

Treatment  of  Solutions 27-46 

Vivian  Refinery 123 

Walker's  Casting  Machine loo 

Witkowitz  Refinery 133 


SHORT-TITLE     CATALOGUE 

OF  THE 

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OF 

JOHN  WILEY   &   SONS, 

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I 


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7 


RAILWAY  ENGINEERING. 


Aadrews's  Handbook  for  Street  Railway  Engineers.  3x5  in  mor.,   1  25 

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8 


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tary   Standpoint 8vo,  2  00 

Richards's  Cost  of  Living  as  Modified  by  Sanitary  Science .  12mo,  1  00 

*  Richards  and  Williams's  The  Dietary  Computer 8vo,  1  60 

Rideal's  Sewage  and  Bacterial  Purification  of  Sewage 8vo,  8  60 

Turneaure  and  Russell's  Public  Water-supplies 8vo,  6  00 

Whipple's  Microscopy  of  Drinking-water 8vo,*  3  60 

Woodhull's  Notes  on  Military  Hygiene 16mo,  1  60 


MISCELLANEOUS. 

Barker's  Deep-sea  Soundings 8vo,  2  00 

Emmous's  Geological  Guide-book  of  the  Rocky  Mountain  Ex- 
cursion   of    the    International    Congress    of    Geologists. 

Large  8  vo,  1  60 

FerreFs  Popular  Treatise  on  the  Winds 8vo,  4  00 

Raines's  American  Railway  Management 12mo,  2  60 

Mott's  Composition,  Digestibility,  and  Nutritive  Value  of  Food. 

Mounted  chart,  1  26 

"      Fallacy  of  the  Present  Theory  of  Sound 16mo,  1  00 

Ricketts's  History  of  Rensselaer  Polytechnic  Institute,  1824- 

1894 Small    8vo,  3  00 

Rotherham's  Emphasised  New  Testament Large  8vo,  S  00 

Steel's  Treatise  on  the  Diseases  of  the  Dog 8vo,  3  60 

Totten's  Important  Question  in  Metrology 8vo,  2  60 

The  World's  Columbian  Exposition  of  1893 4to,  1  00 

Worcester  and  Atkinson.    Small  Hospitals,  Establishment  and 
Maintenance,  and  Suggestions  for  Hospital  Architecture, 

with  Plans  for  a  Small  Hospital 12mo,  1  86 


HEBREW  AND  CHALDEE  TEXT-BOOKS. 

Green's  Grammar  of  the  Hebrew  Language 8vo,  8  00 

"       Elementary  Hebrew  Grammar 12mo,  1  26 

"       Hebrew  Chrestomathy 8vo,  2  00 

Ctoeenius's  Hebrew  and  Chaldee  Lexicon  to  the  Old  Testament 

Scriptures.     (Tregelles.) Small  4to,  nail  morocco,  6  W 

Letteris's  Hebrew  Bible 8vo,  2  26 

16 


-- 


«*BOOK?DUEW 

=fi^MPED  BELOW 

NOV24K^f 


clAN  -  5  1959 


SEP  25  1S19 


ArSj 


YC  18786 


